ilvsillWhich spelling fits?

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

Which to use

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

#7,175
“il” frequency rank
#43,059
“ill” frequency rank
50234
confusion score

Side-by-Side Comparison

Feature il ill
Definition Año. Enfermo.

Where the eye mixes il and ill

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

2 ch
il
3 ch
ill

Why the eye confuses il with ill

These two trip readers on the page rather than in the ear: il is [ˈil] while ill is /ɪl/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “il” sits inside “ill”, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 50234, derived from the frequency rank of both members and their visual similarity.

il is recorded at frequency rank #7,175, classified as anoun, pronounced [ˈil]. ill is at rank #43,059, tagged as anadj, pronounced /ɪl/.

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 50234, this pair ranks #104,344 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of il vs ill

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

"il" · 2 letters · shape VC  ·  "ill" · 3 letters · shape VCC

Frequently Asked Questions

Do "il" and "ill" mean the same thing in a sentence?
No - they are not even the same part of speech. "il" is a noun and "ill" an adjective, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "il" vs "ill" - which ranks higher?
"il" is the more common of the two: it sits at frequency rank #7,175 in our Spanish list, against #43,059 for "ill". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "il" 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 #104,344 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "il" and "ill" also get mixed up with nearby pairs, the highest-scored neighbour is "ill vs iza". Nearby pair

Confusion rank #104,344 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list