50 Idioms for Keeping Secrets (Meanings)

Idioms are special phrases where the words together mean something different from what they say one by one. People use them to make talking and writing more colorful and exciting when describing confidentiality. In this lesson, you will learn fifty unique idioms related to keeping secrets and protecting private information.

In this lesson, we’ll look at idioms that mean hiding facts, staying quiet, or guarding information. Let’s get started and explore some of these helpful expressions.

Idioms for Keeping Secrets

1. Zip your lip

Definition: A quick command to keep your mouth closed and stay quiet.

Used in a Sentence: Remember to zip your lip about the surprise birthday party for mom. / The teacher asked everyone to zip their lip while tests were handed out.

Similar Expressions: Hush up / Keep quiet

2. Seal your lips

Definition: To make a firm promise that you will not reveal private facts.

Used in a Sentence: You must seal your lips regarding our clubhouse plans. / He promised to seal his lips so the surprise would not be ruined.

Similar Expressions: Guard your words / Stay silent

3. Keep it under your hat

Definition: To hide a piece of information and share it with nobody.

Used in a Sentence: I will tell you where we are hiding the gift, but keep it under your hat. / She told her friend the secret plan and said to keep it under your hat.

Similar Expressions: Keep it hidden / Keep it quiet

4. Mum is the word

Definition: A common saying meaning you will say nothing about a topic.

Used in a Sentence: We are planning a party for dad, so mum is the word. / Keep your mouth closed because mum is the word on this project.

Similar Expressions: Say nothing / Total silence

5. Take it to the grave

Definition: A serious promise to keep a secret until the end of your life.

Used in a Sentence: He swore he would take the secret of the hidden treasure to the grave. / Whatever happens here, we will take it to the grave.

Similar Expressions: Ultimate secrecy / Eternal silence

6. Keep a lid on it

Definition: To prevent a secret from leaking out to other people.

Used in a Sentence: We need to keep a lid on our surprise until Friday night. / Make sure you keep a lid on the details of the contest.

Similar Expressions: Contain information / Hide details

7. Play your cards close to your chest

Definition: To keep your plans, thoughts, and secrets completely hidden from others.

Used in a Sentence: When playing board games, he always plays his cards close to his chest. / She likes to play her cards close to her chest when planning class projects.

Similar Expressions: Keep intentions hidden / Guard plans

8. Bite your tongue

Definition: To stop yourself from speaking out or revealing private information.

Used in a Sentence: I had to bite my tongue so I did not ruin the surprise ending of the book. / She bit her tongue instead of telling everyone the news early.

Similar Expressions: Stop talking / Hold your words

9. Lock it away in a vault

Definition: To secure information safely in your mind so it never escapes.

Used in a Sentence: Consider this information locked away in a vault inside my head. / He locked the secret combination away in a mental vault.

Similar Expressions: Secure in mind / Deeply hidden

10. Bury the secret

Definition: To hide information so deeply that nobody can ever find it.

Used in a Sentence: We decided to bury the secret of where we hid the map. / It is best to bury the secret and never mention it again.

Similar Expressions: Hide away / Conceal completely

11. Keep your own counsel

Definition: To keep your thoughts and plans private without asking others for opinions.

Used in a Sentence: Instead of telling everyone, he preferred to keep his own counsel. / She kept her own counsel regarding her surprise art project entry.

Similar Expressions: Keep private thoughts / Remain discreet

12. Not a word to a soul

Definition: A strict instruction to tell absolutely nobody about a private matter.

Used in a Sentence: Remember, not a word to a soul about what you saw here today. / She promised not a word to a soul regarding the hidden puppy.

Similar Expressions: Tell no one / Complete secrecy

13. Hold your tongue

Definition: To keep quiet and refuse to speak about a sensitive topic.

Used in a Sentence: You must hold your tongue if you want the surprise to work. / He told his brother to hold his tongue about the trip.

Similar Expressions: Stay quiet / Keep silent

14. Keep a straight face

Definition: To maintain a calm expression so you do not reveal a secret joke or fact.

Used in a Sentence: It was hard to keep a straight face when my dog wore a silly hat. / She tried to keep a straight face while hiding the birthday gift.

Similar Expressions: Hide your amusement / Remain expressionless

15. Keep it dark

Definition: To keep information completely secret and unrevealed.

Used in a Sentence: Let us keep it dark until the big reveal on Saturday. / He advised his friends to keep it dark about the treehouse location.

Similar Expressions: Keep hidden / Conceal news

16. Keep your lips buttoned

Definition: To keep your mouth shut tightly so no secrets escape.

Used in a Sentence: Keep your lips buttoned if you want to win the game. / The spy nodded and agreed to keep his lips buttoned.

Similar Expressions: Shut your mouth / Stay tight-lipped

17. Safe as a locked box

Definition: Information that is securely hidden and protected from discovery.

Used in a Sentence: Your secret is safe as a locked box with me. / We kept our diary entries safe as a locked box in the drawer.

Similar Expressions: Securely guarded / Protected tightly

18. Put a lock on your lips

Definition: A physical gesture command to stop talking and hide secrets.

Used in a Sentence: Put a lock on your lips and do not mention the prize. / The children put a lock on their lips when the teacher walked by.

Similar Expressions: Close tight / Shut up

19. Keep things under wraps

Definition: To keep a project or piece of news hidden from public view.

Used in a Sentence: The studio kept the new movie trailer strictly under wraps. / We need to keep our club plans under wraps until next week.

Similar Expressions: Hide details / Conceal plans

20. Hold your breath and say nothing

Definition: Staying completely still and quiet to protect a secret.

Used in a Sentence: When we heard footsteps, we held our breath and said nothing. / He stayed quiet and held his breath so nobody would find us.

Similar Expressions: Stay hidden / Remain motionless

21. Bury deep in your heart

Definition: To hold a personal secret cherished inside your emotions.

Used in a Sentence: She decided to bury the memory deep in her heart. / Keep this promise buried deep in your heart forever.

Similar Expressions: Cherish privately / Guard emotionally

22. Not breathe a word

Definition: To refuse to speak even a single syllable about a topic.

Used in a Sentence: Promise you will not breathe a word of this to anyone at school. / He shook his head and swore not to breathe a word.

Similar Expressions: Say nothing / Keep silent

23. Keep behind closed doors

Definition: Keeping discussions and secrets hidden away from outsiders.

Used in a Sentence: The team kept their strategy meeting behind closed doors. / All planning took place behind closed doors to avoid leaks.

Similar Expressions: Private meeting / Hidden discussion

24. Play dumb

Definition: To pretend you do not know a secret when people ask you about it.

Used in a Sentence: When they asked about the party, I just had to play dumb. / He played dumb so nobody would suspect he knew the answer.

Similar Expressions: Act ignorant / Feign innocence

25. Keep out of sight

Definition: To hide information or items so people cannot see them.

Used in a Sentence: Keep the wrapped present out of sight in the closet. / We made sure our clubhouse maps stayed out of sight.

Similar Expressions: Hide away / Conceal well

26. Keep a secret safe

Definition: To protect private information from being shared with others.

Used in a Sentence: It is important to know how to keep a secret safe. / She promised to keep a secret safe for her best friend.

Similar Expressions: Guard secrets / Protect facts

27. Sworn to secrecy

Definition: Formally promising through an oath to keep information hidden.

Used in a Sentence: Every club member was sworn to secrecy before joining. / We were sworn to secrecy about the magic show tricks.

Similar Expressions: Bound by oath / Pledged to silence

28. Hide your hand

Definition: To conceal your true intentions or plans from onlookers.

Used in a Sentence: During negotiations, it is wise to hide your hand. / He decided to hide his hand until the final round of the game.

Similar Expressions: Conceal plans / Mask intentions

29. Keep the cat in the bag

Definition: Keeping a secret securely contained so it is not revealed.

Used in a Sentence: We managed to keep the cat in the bag regarding the vacation spot. / Keeping the cat in the bag is harder than it sounds.

Similar Expressions: Maintain secrecy / Guard surprise

30. Cloak and dagger

Definition: Describing secret, mysterious activities and hidden plots.

Used in a Sentence: Passing notes in class felt like a cloak and dagger operation. / The mystery club loved playing cloak and dagger games.

Similar Expressions: Mysterious and secret / Stealthy plotting

31. Under the radar

Definition: Doing something quietly without drawing any attention or questions.

Used in a Sentence: We planned the surprise party completely under the radar. / He managed to finish his secret project right under the radar.

Similar Expressions: Quietly done / Unnoticed action

32. Keep a tight rein on your words

Definition: To carefully control what you say so you do not spill secrets.

Used in a Sentence: You must keep a tight rein on your words during lunch. / She kept a tight rein on her words around chatty classmates.

Similar Expressions: Control speech / Watch your tongue

33. Keep your mouth shut

Definition: A blunt way to tell someone not to reveal any information.

Used in a Sentence: If you want this plan to work, keep your mouth shut. / He reminded everyone to keep their mouths shut about the shortcut.

Similar Expressions: Stay quiet / Shut up

34. Off the record

Definition: Information shared privately that should not be published or repeated.

Used in a Sentence: What I am about to tell you is strictly off the record. / The reporter listened to the coach’s comments off the record.

Similar Expressions: Private info / Confidential note

35. Keep a low profile

Definition: To behave quietly and avoid drawing notice while hiding a plan.

Used in a Sentence: We decided to keep a low profile while preparing the surprise. / Staying indoors helped us keep a low profile all afternoon.

Similar Expressions: Stay unnoticed / Be discreet

36. Keep under lock and key

Definition: To store secrets or physical items in a secure hiding spot.

Used in a Sentence: The diary was kept under lock and key in her desk drawer. / We kept the prize tokens under lock and key.

Similar Expressions: Securely locked / Protected safely

37. Hush-hush

Definition: Describing a topic that is treated with intense secrecy and quiet.

Used in a Sentence: The new school project was very hush-hush among the teachers. / They spoke in a hush-hush tone about the upcoming assembly.

Similar Expressions: Highly confidential / Very secret

38. Keep it on the down low

Definition: A modern way to say you should keep information very quiet.

Used in a Sentence: Let us keep this news on the down low until tomorrow. / He asked me to keep our hiking spot on the down low.

Similar Expressions: Keep it quiet / Discreet sharing

39. Play it close to the vest

Definition: To keep your plans and secrets completely hidden from view.

Used in a Sentence: She plays it close to the vest when preparing her science projects. / Playing it close to the vest helps protect your ideas.

Similar Expressions: Guard plans / Keep hidden

40. Keep your own counsel on matters

Definition: Relying only on yourself and sharing no private information.

Used in a Sentence: He learned early on to keep his own counsel on matters of importance. / She practiced keeping her own counsel regarding her goals.

Similar Expressions: Remain private / Trust yourself

41. Confidential and quiet

Definition: Keeping information restricted to a trusted circle of people.

Used in a Sentence: The document marked confidential and quiet sat on the desk. / Our group discussion remained confidential and quiet.

Similar Expressions: Strictly private / Secure talk

42. Keep a tight lip

Definition: To close your mouth firmly and reveal no secrets.

Used in a Sentence: Keep a tight lip if anyone asks about the missing puzzle piece. / He promised to keep a tight lip during the investigation.

Similar Expressions: Stay silent / Button up

43. Keep silent

Definition: To refuse to make any sound or share any words.

Used in a Sentence: The librarian asked us to keep silent in the reading room. / We had to keep silent while hiding from our friends.

Similar Expressions: Remain quiet / Make no noise

44. Guard the secret

Definition: To protect private information like a watchful sentinel.

Used in a Sentence: It is our duty to guard the secret until the party starts. / She promised to guard the secret with all her heart.

Similar Expressions: Protect information / Keep safe

45. Conceal the truth

Definition: To hide factual information so nobody discovers it.

Used in a Sentence: He tried to conceal the truth about who ate the cookies. / Hiding mistakes is never as good as being honest instead of concealing truth.

Similar Expressions: Hide facts / Mask reality

46. Keep things quiet

Definition: To maintain a peaceful, secret atmosphere without gossip.

Used in a Sentence: Please try to keep things quiet about our hiding spot. / The manager wanted to keep things quiet regarding the schedule change.

Similar Expressions: Maintain peace / Avoid noise

47. Keep off the grapevine

Definition: Preventing information from spreading through neighborhood gossip.

Used in a Sentence: We kept our family news off the grapevine. / Keeping plans off the grapevine stops rumors from starting.

Similar Expressions: Stop gossip / Avoid rumors

48. Bury the details

Definition: To hide specific facts so people do not ask questions.

Used in a Sentence: He tried to bury the details of how the vase broke. / We buried the details of our scavenger hunt path.

Similar Expressions: Hide facts / Conceal specifics

49. Keep under wraps tightly

Definition: To secure information with extra care and precaution.

Used in a Sentence: We kept our art exhibit theme under wraps tightly. / Keeping the project under wraps tightly ensures a big surprise.

Similar Expressions: Securely hidden / Strictly guarded

50. Lock your lips and throw away the key

Definition: A dramatic expression promising never to tell a secret.

Used in a Sentence: Lock your lips and throw away the key about this treasure map. / She promised to lock her lips and throw away the key.

Similar Expressions: Eternal secrecy / Permanent silence

Exercise to Practice

1. Remember to zip your lip about the surprise birthday party for mom.
2. You must seal your lips regarding our messy bedroom cleaning plans.
3. I will tell you where we are hiding the gift, but keep it under your hat.
4. We are planning a loud party for dad, so mum is the word by shouting.
5. He swore he would take the secret of the hidden treasure to the grave.
6. We need to keep a lid on our surprise until Friday night dinner.
7. When playing board games, he always plays his cards close to his chest.
8. I had to bite my tongue so I did not ruin the surprise ending of the book.
9. Consider this information locked away in an open playground sandbox.
10. We decided to bury the secret of where we hid the map in the yard.
11. Instead of telling everyone, he preferred to keep his own loud voice.
12. Remember, not a word to a soul about what you saw here today.
13. You must hold your tongue if you want the surprise to work properly.
14. It was hard to keep a straight face when my dog wore a silly hat.
15. Let us keep it dark by turning on all the bright ceiling lights.

Answer Key

1. True
2. False
3. True
4. False
5. True
6. True
7. True
8. True
9. False
10. True
11. False
12. True
13. True
14. True
15. False

Conclusion

Learning these idioms helps you describe keeping secrets and protecting private information in creative and colorful ways. Expanding your everyday vocabulary makes your stories and conversations much more engaging for everyone around you.

Try using one or two of these expressions the next time you talk with your friends or family members. You will see how much fun it is to express your thoughts using vivid English phrases.

Frequently Asked Questions

What are some common idioms for keeping secrets?

Common idioms include phrases like zip your lip, keep it under your hat, and mum is the word. These expressions give a clear picture of staying quiet and protecting information.

Why do we use idioms in English?

Idioms make our language more vibrant, colorful, and fun to speak. Instead of plain descriptions, they let us share feelings and actions in creative ways.

How can I practice using idioms easily?

You can practice by picking one new idiom each day and using it in a sentence with a friend. Writing short stories or making up funny sentences also helps you remember them.

Are idioms difficult for beginners to learn?

Not at all, especially when you learn them through relatable topics like surprises and secrets. Context and example sentences make it easy to understand what they mean right away.

Can I use these idioms in school writing?

Yes, using idioms can make your stories and essays much more creative and fun to read. Just make sure you use them correctly so your meaning is clear to your teacher.