Which to use
“unsuccessful” is an adjective and “unsuccessfully” is an adverb - they look or sound alike but fill different roles in a sentence.
- #10,789
- “unsuccessful” frequency rank
- #20,257
- “unsuccessfully” frequency rank
- 31046
- confusion score
Side-by-Side Comparison
| Feature | unsuccessful | unsuccessfully |
|---|---|---|
| Definition | Failed, not successful. | Not successfully; without success; to no avail. |
Where the spellings diverge
Shared letters are muted; the letters that actually set unsuccessful and unsuccessfully apart are highlighted. They share 12 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
These two trip readers on the page rather than in the ear: unsuccessful is /ˌʌnsəkˈsɛsfl̩/ while unsuccessfully is /ˌʌnsəkˈsɛsfəli/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 extra letter(s) - “unsuccessful” sits inside “unsuccessfully”, and the parts of speech differ too (adjective vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 31046, derived from the frequency rank of both members and their visual similarity.
unsuccessful is recorded at frequency rank #10,789, classified as anadj, pronounced /ˌʌnsəkˈsɛsfl̩/. unsuccessfully is at rank #20,257, tagged as anadv, pronounced /ˌʌnsəkˈsɛsfəli/.
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 31046, this pair ranks #349,475 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of unsuccessful vs unsuccessfully
Shared letters: ceflnsu. Private to "unsuccessful": -. Private to "unsuccessfully": y.
"unsuccessful" · 12 letters · shape VCCVCCVCCCVC · "unsuccessfully" · 14 letters · shape VCCVCCVCCCVCCV
Known mistypes of this pair
- unsuccessful ← nusuccessful · unnsuccessful · unscucessful · unssuccessful · unsuccesfsul · unsuccesful · unsuccessfful · unsuccessflu
- unsuccessfully ← nusuccessfully · unnsuccessfully · unscucessfully · unssuccessfully · unsuccesfsully · unsuccesfully · unsuccessffully · unsuccessfluly
Frequency comparison
Frequently Asked Questions
Can "unsuccessful" and "unsuccessfully" be used interchangeably?
Which is more common, "unsuccessful" or "unsuccessfully"?
Remembering unsuccessful vs unsuccessfully
The fastest way to pick the right one every time.
- Check the role first: if you need an adjective, it's “unsuccessful”; for an adverb, it's “unsuccessfully”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “unsuccessful” entry
- Browse more pairs most likely to be confused. Most confusable