# deflate

/dɪˈfɫeɪt/ (US) · /diːflˈeɪt/ (UK) · CEFR B2 · Verb

Source: https://englishreference.com/word/deflate
Updated: 2026-10-18

## Definition

to let air or gas out of something like a balloon or tyre, so it becomes smaller and flat. You also use it when someone suddenly feels less confident or excited.

For teachers: to release air or gas from an inflated object, causing it to shrink or collapse. Extended to abstract contexts, to reduce the size, value, or confidence associated with something.

## Examples

- I deflate the air mattress after guests leave.
- The mechanic noticed the tyre was overfilled and deflated it slightly before the long drive.
- The unexpected criticism seemed to deflate his enthusiasm for the project he had championed for months.

## Synonyms

discourage, disappoint

## Antonyms

inflate, encourage

## Usage notes

- Transitive and takes a direct object; also used figuratively with abstract nouns such as confidence, ego, or prices.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.