Which to use
“fast” is an adjective and “FSB” is a name - they look or sound alike but fill different roles in a sentence.
- #767
- “fast” frequency rank
- #32,815
- “FSB” frequency rank
- 33582
- confusion score
Side-by-Side Comparison
| Feature | fast | FSB |
|---|---|---|
| Definition | Firmly or securely fixed in place; stable. | The Federal Security Service of the Russian Federation. |
Letter map: fast vs FSB
Shared letters muted; letters that set fast and FSB apart highlighted. Shared run: 2.
Spelling & Dictionary Insight
Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: fast is anadjective and FSBaname. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 33582, derived from the frequency rank of both members and their visual similarity.
fast is recorded at frequency rank #767, classified as anadj, pronounced /fɑːst/. FSB is at rank #32,815, tagged as aname.
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 33582, this pair ranks #328,150 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fast vs FSB
Shared letters: fs. Private to "fast": at. Private to "FSB": b.
"fast" · 4 letters · shape CVCC · "FSB" · 3 letters · shape CCC
Known mistypes of this pair
- fast ← afst · fasst · fastt · ffast · fsat