# under the illusion

idiom

Source: https://englishreference.com/idiom/under-the-illusion
Updated: 2026-08-10

## Meaning

Having a mistaken belief about something.

## Examples

- He is under the illusion that he can win.
- She was under the illusion that the project would be easy, but it took much longer than expected.
- The politician remained under the illusion that the public still supported his policies, despite the overwhelming evidence of his declining popularity.

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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.