Which to use
“fasten” is a verb and “fastest” is an adjective - they look or sound alike but fill different roles in a sentence.
- #29,649
- “fasten” frequency rank
- #4,759
- “fastest” frequency rank
- 34408
- confusion score
Side-by-Side Comparison
| Feature | fasten | fastest |
|---|---|---|
| Definition | To attach or connect in a secure manner. | superlative form of fast (adjective): most fast |
Letter map: fasten vs fastest
Shared letters muted; letters that set fasten and fastest apart highlighted. Shared run: 5. fasten runs 6 letters (CVCCVC) against fastest's 7 (CVCCVCC) - the length gap alone is often enough to separate them once you know to check it.
Part-of-speech tell for fasten / fastest
Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: fasten is averb and fastestanadjective. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 34408, derived from the frequency rank of both members and their visual similarity.
fasten is recorded at frequency rank #29,649, classified as averb, pronounced /ˈfɑːsn̩/. fastest is at rank #4,759, tagged as anadj.
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 34408, this pair ranks #321,049 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fasten vs fastest
Shared letters: aefst. Private to "fasten": n. Private to "fastest": -.
"fasten" · 6 letters · shape CVCCVC · "fastest" · 7 letters · shape CVCCVCC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "fasten" for "fastest" ever safe?
Frequency check: "fasten" vs "fastest" - which ranks higher?
After this comparison
Done with this confusable. These links stay specific to "fasten" and "fastest".
- Full dictionary entry for "fasten" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "fastest" - compare definitions side by side with the headword page. Word entry
- This pair ranks #321,049 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "fasten" and "fastest" also get mixed up with nearby pairs, the highest-scored neighbour is "fasten vs fastener". 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 #321,049 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.