keep in

not show or express (feelings, emotions)

B2

What does "keep sth in" mean?

To keep something in means to stop it from coming out or escaping — whether that's an emotion, a person, or something physical like heat. In emotional contexts, it means suppressing a feeling and not letting others see it, for example holding back tears or hiding your frustration. In a physical sense, it can describe confining a person to a place, such as police holding a suspect overnight or a teacher keeping a student behind after class. It also describes retaining something like warmth or heat inside a space, for instance when insulation stops the cold from taking over. All three senses share the same core idea: something that could leave or be expressed is being held inside.

Examples

How to use it

keep + object + in

The most common structure, especially when the object is a pronoun or short noun phrase — the object goes between 'keep' and 'in'.

He felt like crying but managed to keep the tears in throughout the meeting.

keep + pronoun + in

When the object is a pronoun, it must go between 'keep' and 'in' — placing it after 'in' is always wrong.

She was furious, but she kept it in and waited until she got home to vent.

be kept in + (time phrase / purpose phrase)

The passive form is natural when describing a person being confined, often with a time phrase or reason.

Two of the players were kept in after training to work on their technique.

keep + object + in + (purpose/context phrase)

Used when explaining why or where someone is being confined, common in news or official contexts.

The police kept the suspect in overnight while they gathered more evidence.

keep the + noun + in

Used for physical substances like heat, warmth, or cold air — here the object is always a noun, not a pronoun.

We put a draught excluder under the door to keep the warmth in.

Common Collocations

keep your emotions inkeep the heat inkeep him/her inkeep the tears inkeep the warmth inkeep a prisoner in

Common Mistakes

Pronoun placed after 'in'

With pronoun objects, the pronoun must go between 'keep' and 'in'. Placing it after 'in' is incorrect and sounds unnatural to native speakers.

✗ She was upset but managed to keep in it.
✓ She was upset but managed to keep it in.
Confusing 'keep in' with 'keep out'

'Keep in' means to retain something inside, while 'keep out' means to prevent something from entering. These are opposite directions, so mixing them up changes the meaning entirely.

✗ The new windows keep the cold in much better than the old ones.
✓ The new windows keep the cold out much better than the old ones. / The new windows keep the heat in much better than the old ones.
Confusing 'keep in' with 'keep in with'

Adding 'with' after 'keep in' creates a completely different phrasal verb meaning to stay on good terms with someone. Make sure you're not mixing up the two.

✗ She kept in her colleagues by being friendly and helpful.
✓ She kept in with her colleagues by being friendly and helpful. (= maintained good relations) / She kept her feelings in and said nothing. (= suppressed)

Usage

This phrasal verb is neutral in register and works in both spoken and written English. The emotional sense ('keep your feelings in') is especially common in informal speech and narrative writing.

Frequently Asked Questions

Can 'keep in' be used for all three meanings — emotions, people, and heat — or just one?

It genuinely covers all three senses, and which one is meant is usually clear from context. 'Keep your feelings in' is about emotion, 'keep the suspect in' is about confinement, and 'keep the warmth in' is about retaining heat. If you're unsure whether your sentence is clear, adding a small context clue (like mentioning 'insulation' or 'overnight') can help.

Can I say 'I was keeping in my laughter' — does it work with the past continuous?

This tense can feel a little awkward with 'keep in'. It's more natural to use the past simple or an infinitive after a modal: 'I kept my laughter in' or 'I had to keep my laughter in'. The past continuous isn't impossible, but native speakers would usually choose a different structure.

Is 'kept in' the right past form for both emotions and confinement?

Yes — the past simple 'kept in' works for all senses. For example: 'She kept her frustration in all day' (emotion) and 'He was kept in for questioning' (confinement). Both are completely natural.

What kinds of emotions can you 'keep in'?

The most common collocations are tears, anger, laughter, frustration, feelings, and pain. More generally, any emotion you're trying not to show or express can work. Avoid very abstract or formal nouns like 'trepidation' — they sound unnatural in this construction.

Can 'keep in' be used without an object?

No — 'keep in' always needs an object in this sense. You need to specify what is being held back or retained, whether that's a pronoun ('keep it in') or a noun ('keep the heat in'). An intransitive use like 'she kept in' on its own is not standard.

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