Which to use
“impair” is a verb and “impaired” is an adjective - they look or sound alike but fill different roles in a sentence.
- #31,616
- “impair” frequency rank
- #11,558
- “impaired” frequency rank
- 43174
- confusion score
Side-by-Side Comparison
| Feature | impair | impaired |
|---|---|---|
| Definition | To weaken; to affect negatively; to have a diminishing effect on. | Rendered less effective. |
Where the eye mixes impair and impaired
Muted = shared; highlighted = the visual trap. They share 6 letters in sequence. impair runs 6 letters (VCCVVC) against impaired's 8 (VCCVVCVC) - the length gap alone is often enough to separate them once you know to check it.
Why the eye confuses impair with impaired
These two trip readers on the page rather than in the ear: impair is /ɪmˈpɛə(ɹ)/ while impaired is /ɪmˈpɛrd/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 extra letter(s) - “impair” sits inside “impaired”, and the parts of speech differ too (verb vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 43174, derived from the frequency rank of both members and their visual similarity.
impair is recorded at frequency rank #31,616, classified as averb, pronounced /ɪmˈpɛə(ɹ)/. impaired is at rank #11,558, tagged as anadj, pronounced /ɪmˈpɛrd/.
Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.
With a confusion score of 43174, this pair ranks #242,525 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of impair vs impaired
Shared letters: aimpr. Private to "impair": -. Private to "impaired": de.
"impair" · 6 letters · shape VCCVVC · "impaired" · 8 letters · shape VCCVVCVC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "impair" for "impaired" ever safe?
Frequency check: "impair" vs "impaired" - which ranks higher?
What to do next
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "impair" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "impaired" - compare definitions side by side with the headword page. Word entry
- This pair ranks #242,525 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "impair" and "impaired" also get mixed up with nearby pairs, the highest-scored neighbour is "impair vs impala". Nearby pair
- Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes
Confusion rank #242,525 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.