Which to use
“ruff” and “rust” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #27,272
- “ruff” frequency rank
- #10,604
- “rust” frequency rank
- 37876
- confusion score
Side-by-Side Comparison
| Feature | ruff | rust |
|---|---|---|
| Definition | A circular frill or ruffle on a garment, especially a starched, fluted frill at the neck in Elizabethan and Jacobean England (1560s–1620s). | The deteriorated state of iron or steel as a result of moisture and oxidation; it consists mostly of iron(III) oxide (ferric oxide) and iron(II) oxide (ferrous oxide). |
Where the eye mixes ruff and rust
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.
Why the eye confuses ruff with rust
A purely visual mix-up. ruff (/ɹʌf/) and rust (/ɹʌst/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 37876, derived from the frequency rank of both members and their visual similarity.
ruff is recorded at frequency rank #27,272, classified as anoun, pronounced /ɹʌf/. rust is at rank #10,604, tagged as anoun, pronounced /ɹʌst/.
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 37876, this pair ranks #290,719 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of ruff vs rust
Shared letters: ru. Private to "ruff": f. Private to "rust": st.
"ruff" · 4 letters · shape CVCC · "rust" · 4 letters · shape CVCC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "ruff" for "rust" ever safe?
Which is more common, "ruff" or "rust"?
What to do next
Eye-level mix-up between "ruff" and "rust" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "ruff" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "rust" - compare definitions side by side with the headword page. Word entry
- This pair ranks #290,719 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "ruff" and "rust" also get mixed up with nearby pairs, the highest-scored neighbour is "Rua vs ruff". 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 #290,719 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.