IH vs ill, What's the Difference?

Which to use

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

#35,767
“IH” frequency rank: #1,946
“ill” frequency rank: 37713
confusion score

Side-by-Side Comparison

Feature	IH	ill
Definition	Initialism of industrial hygiene.	Evil; wicked (of people).

Letter map: IH vs ill

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

2 ch

3 ch

ill

Part-of-speech tell for IH / ill

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: IH is anoun and illanadjective. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 37713, derived from the frequency rank of both members and their visual similarity.

IH is recorded at frequency rank #35,767, classified as anoun. ill is at rank #1,946, 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 37713, this pair ranks #292,165 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of IH vs ill

Shared letters: i. Private to "IH": h. Private to "ill": l.

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

Frequently Asked Questions

Do "IH" and "ill" mean the same thing in a sentence?

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

Which is more common, "IH" or "ill"?

"ill" is the more common of the two: it sits at frequency rank #1,946 in our English list, against #35,767 for "IH". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Done with this confusable. These links stay specific to "IH" and "ill".

Full dictionary entry for "IH" 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 #292,165 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
"IH" and "ill" also get mixed up with nearby pairs, the highest-scored neighbour is "IH vs ith". Nearby pair

Confusion rank #292,165 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.