Which to use
“ii” is an adverb and “ill” is an adjective - they look or sound alike but fill different roles in a sentence.
- #627
- “ii” frequency rank
- #15,649
- “ill” frequency rank
- 16276
- confusion score
Side-by-Side Comparison
| Feature | ii | ill |
|---|---|---|
| Definition | Oui. | Malade, malsain. |
Where the eye mixes ii and ill
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Why the eye confuses ii with ill
These two trip readers on the page rather than in the ear: ii is \iː\ while ill is \ˈɪl\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (adverb vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 16276, derived from the frequency rank of both members and their visual similarity.
ii is recorded at frequency rank #627, classified as anadv, pronounced \iː\. ill is at rank #15,649, tagged as anadj, pronounced \ˈɪl\.
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 16276, this pair ranks #388,566 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of ii vs ill
Shared letters: i. Private to "ii": -. Private to "ill": l.
"ii" · 2 letters · shape VV · "ill" · 3 letters · shape VCC
Frequently Asked Questions
Is swapping "ii" for "ill" ever safe?
Frequency check: "ii" vs "ill" - which ranks higher?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "ii" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "ill" - compare definitions side by side with the headword page. Word entry
- This pair ranks #388,566 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "ii" and "ill" also get mixed up with nearby pairs, the highest-scored neighbour is "ill vs isi". Nearby pair
Confusion rank #388,566 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.