ifvsillTell them apart

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

Which to use

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

#7,069
“if” frequency rank
#15,649
“ill” frequency rank
22718
confusion score

Side-by-Side Comparison

Feature if ill
Definition Arbre sempervirent de la famille des taxacées, à feuilles persistantes longues, étroites, vénéneuses, d’un vert très sombre, à fausses baies rouges, utilisé comme arbre d’ornement dans les parcs, les jardins, les cimetières, et plus spécialement l’if commun (Taxus baccata). Malade, malsain.

Where the eye mixes if and ill

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

2 ch
if
3 ch
ill

Look-alike desk: if vs ill

These two trip readers on the page rather than in the ear: if is \if\ while ill is \ˈɪl\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 22718, derived from the frequency rank of both members and their visual similarity.

if is recorded at frequency rank #7,069, classified as anoun, pronounced \if\. ill is at rank #15,649, tagged as anadj, pronounced \ˈɪl\.

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 22718, this pair ranks #356,528 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of if vs ill

Shared letters: i. Private to "if": f. Private to "ill": l.

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

Frequently Asked Questions

Is swapping "if" for "ill" ever safe?
No - they are not even the same part of speech. "if" is a noun and "ill" an adjective, so a sentence built for one is usually ungrammatical with the other.
In ordinary French text, does "if" or "ill" show up more?
"if" is the more common of the two: it sits at frequency rank #7,069 in our French list, against #15,649 for "ill". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "if" 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 #356,528 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "if" and "ill" also get mixed up with nearby pairs, the highest-scored neighbour is "ill vs isi". Nearby pair

Confusion rank #356,528 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list