Which to use
“ill” is an adjective and “iso” is a noun - they look or sound alike but fill different roles in a sentence.
- #1,946
- “ill” frequency rank
- #9,771
- “iso” frequency rank
- 11717
- confusion score
Side-by-Side Comparison
| Feature | ill | iso |
|---|---|---|
| Definition | Evil; wicked (of people). | Clipping of isolation. |
Where the eye mixes ill and iso
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Look-alike desk: ill vs iso
These two trip readers on the page rather than in the ear: ill is /ɪl/ while iso is /ˈaɪsəʊ/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 11717, derived from the frequency rank of both members and their visual similarity.
ill is recorded at frequency rank #1,946, classified as anadj, pronounced /ɪl/. iso is at rank #9,771, tagged as anoun, pronounced /ˈaɪsəʊ/.
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 11717, this pair ranks #485,508 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of ill vs iso
Shared letters: i. Private to "ill": l. Private to "iso": os.
"ill" · 3 letters · shape VCC · "iso" · 3 letters · shape VCV
Frequently Asked Questions
Can "ill" and "iso" be used interchangeably?
Which is more common, "ill" or "iso"?
Useful next steps
Eye-level mix-up between "ill" and "iso" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "ill" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "iso" - compare definitions side by side with the headword page. Word entry
- This pair ranks #485,508 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "ill" and "iso" also get mixed up with nearby pairs, the highest-scored neighbour is "iso vs ith". Nearby pair
Confusion rank #485,508 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.