illvsillsWhich spelling fits?

Quick tell: ill is a adjective, ills is a noun, so they fill different roles in a sentence.

Which to use

“ill” is an adjective and “ills” is a noun - they look or sound alike but fill different roles in a sentence.

#1,946
“ill” frequency rank
#28,587
“ills” frequency rank
30533
confusion score

Side-by-Side Comparison

Feature ill ills
Definition Evil; wicked (of people). plural of ill

Where the eye mixes ill and ills

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.

3 ch
ill
4 ch
ills

Look-alike desk: ill vs ills

These two trip readers on the page rather than in the ear: ill is /ɪl/ while ills is /ɪlz/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “ill” sits inside “ills”, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 30533, 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/. ills is at rank #28,587, tagged as anoun, pronounced /ɪlz/.

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 30533, this pair ranks #353,763 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of ill vs ills

Shared letters: il. Private to "ill": -. Private to "ills": s.

"ill" · 3 letters · shape VCC  ·  "ills" · 4 letters · shape VCCC

Known mistypes of this pair

  • illsillss · ilsl · lils

Frequently Asked Questions

Can "ill" and "ills" be used interchangeably?
No - they are not even the same part of speech. "ill" is an adjective and "ills" a noun, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "ill" vs "ills" - which ranks higher?
"ill" is the more common of the two: it sits at frequency rank #1,946 in our English list, against #28,587 for "ills". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Eye-level mix-up between "ill" and "ills" 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 "ills" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #353,763 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "ill" and "ills" also get mixed up with nearby pairs, the highest-scored neighbour is "Ilan vs ills". 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 #353,763 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list