# rule out

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/rule-out
Updated: 2026-10-22

## Definition

to decide that something is not possible or to remove it from a list of options.

For teachers: to exclude a possibility, person, or cause from consideration. Transitive; the object may be a noun phrase or a clause.

## Examples

- The doctor wants to rule out any serious illness.
- After checking the security footage, the police were able to rule out the first suspect because he was at home.
- While the initial data suggested a mechanical failure, the investigators cannot yet rule out the possibility of human error or external interference in the crash.

## Pitfalls

- Not "We can rule out of that option." but "We can rule out that option." — the particle 'out' is not followed by 'of' when used as a phrasal verb meaning to exclude.

## Usage notes

- commonly used with nouns like 'possibility', 'chance', or 'option'.
- Teaching tip: useful for discussing problem-solving or medical diagnoses; highlight that it is often used in the negative ('cannot rule out').

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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.