Which to use
“sudden” and “sullen” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #3,659
- “sudden” frequency rank
- #41,399
- “sullen” frequency rank
- 45058
- confusion score
Side-by-Side Comparison
| Feature | sudden | sullen |
|---|---|---|
| Definition | Occurring quickly with little or no warning or expectation; instantly. | Having a brooding ill temper; sulky. |
Where the eye mixes sudden and sullen
Muted = shared; highlighted = the visual trap. They share 4 letters in sequence. sudden and sullen follow the identical consonant-vowel pattern (CVCCVC). Same shape at a glance is often the real trap, independent of shared letters.
Look-alike desk: sudden vs sullen
A purely visual mix-up. sudden (/ˈsʌdn̩/) and sullen (/ˈsʌlən/) 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 45058, derived from the frequency rank of both members and their visual similarity.
sudden is recorded at frequency rank #3,659, classified as anadj, pronounced /ˈsʌdn̩/. sullen is at rank #41,399, tagged as anadj, pronounced /ˈsʌlən/.
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 45058, this pair ranks #224,789 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of sudden vs sullen
Shared letters: ensu. Private to "sudden": d. Private to "sullen": l.
"sudden" · 6 letters · shape CVCCVC · "sullen" · 6 letters · shape CVCCVC
Known mistypes of this pair
Frequently Asked Questions
Do "sudden" and "sullen" mean the same thing in a sentence?
In ordinary English text, does "sudden" or "sullen" show up more?
What to do next
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "sudden" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "sullen" - compare definitions side by side with the headword page. Word entry
- This pair ranks #224,789 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "sudden" and "sullen" also get mixed up with nearby pairs, the highest-scored neighbour is "silken vs sullen". 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 #224,789 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.