ill vs is, What's the Difference?

Which to use

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

#44,899
“ill” frequency rank: #1,709
“is” frequency rank: 46608
confusion score

Side-by-Side Comparison

Feature	ill	is
Definition	doente	contração de agus; e

Letter map: ill vs is

Shared letters muted; letters that set ill and is apart highlighted. Shared run: 1.

3 ch

ill

2 ch

Role in the sentence - ill and is

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: ill is anadjective and isaverb. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 46608, derived from the frequency rank of both members and their visual similarity.

ill is recorded at frequency rank #44,899, classified as anadj, pronounced /ɪl/. is is at rank #1,709, tagged as averb.

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 46608, this pair ranks #18,697 of 75,631 scored Portuguese confusable pairs - among the most confusable pairs.

Orthographic DNA of ill vs is

Shared letters: i. Private to "ill": l. Private to "is": s.

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

Frequently Asked Questions

Can "ill" and "is" be used interchangeably?

No - they are not even the same part of speech. "ill" is an adjective and "is" a verb, so a sentence built for one is usually ungrammatical with the other.

Frequency check: "ill" vs "is" - which ranks higher?

"is" is the more common of the two: it sits at frequency rank #1,709 in our Portuguese list, against #44,899 for "ill". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Pair "ill" vs "is" is on the table, pick a follow-up below.

Full dictionary entry for "ill" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "is" - compare definitions side by side with the headword page. Word entry
This pair ranks #18,697 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"ill" and "is" also get mixed up with nearby pairs, the highest-scored neighbour is "ill vs ino". Nearby pair

Confusion rank #18,697 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.