idlevsillTell them apart

Which to use

“idle” and “ill” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#11,235
“idle” frequency rank
#1,946
“ill” frequency rank
13181
confusion score

Side-by-Side Comparison

Feature idle ill
Definition Empty, vacant. Evil; wicked (of people).

Where the eye mixes idle and ill

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

4 ch
idle
3 ch
ill

Why the eye confuses idle with ill

A purely visual mix-up. idle (/ˈaɪd(ə)l/) and ill (/ɪl/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 letter(s) in length. Our composite confusion score for this pair is 13181, derived from the frequency rank of both members and their visual similarity.

idle is recorded at frequency rank #11,235, classified as anadj, pronounced /ˈaɪd(ə)l/. 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 13181, this pair ranks #477,327 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of idle vs ill

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

"idle" · 4 letters · shape VCCV  ·  "ill" · 3 letters · shape VCC

Known mistypes of this pair

  • idledile · iddle · idel · idlle · ilde

Frequently Asked Questions

Is swapping "idle" for "ill" ever safe?
No. They are said differently (/ˈaɪd(ə)l/ versus /ɪl/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "idle" or "ill"?
"ill" is the more common of the two: it sits at frequency rank #1,946 in our English list, against #11,235 for "idle". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

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

  • Full dictionary entry for "idle" 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 #477,327 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "idle" and "ill" also get mixed up with nearby pairs, the highest-scored neighbour is "idle vs IME". 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 #477,327 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