fastvsFSAWhat's the difference?

Quick tell: fast is a adjective, FSA is a noun, so they fill different roles in a sentence.

Which to use

“fast” is an adjective and “FSA” is a noun - they look or sound alike but fill different roles in a sentence.

#767
“fast” frequency rank
#24,161
“FSA” frequency rank
24928
confusion score

Side-by-Side Comparison

Feature fast FSA
Definition Firmly or securely fixed in place; stable. Initialism of flexible spending account or flexible spending arrangement.

Letter map: fast vs FSA

Shared letters muted; letters that set fast and FSA apart highlighted. Shared run: 2.

4 ch
fast
3 ch
FSA

Spelling & Dictionary Insight

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: fast is anadjective and FSAanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 24928, derived from the frequency rank of both members and their visual similarity.

fast is recorded at frequency rank #767, classified as anadj, pronounced /fɑːst/. FSA is at rank #24,161, tagged as anoun.

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 24928, this pair ranks #398,240 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fast vs FSA

Shared letters: afs. Private to "fast": t. Private to "FSA": -.

"fast" · 4 letters · shape CVCC  ·  "FSA" · 3 letters · shape CCV

Known mistypes of this pair

  • fastafst · fasst · fastt · ffast · fsat

Frequently Asked Questions

Can "fast" and "FSA" be used interchangeably?
No - they are not even the same part of speech. "fast" is an adjective and "FSA" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "fast" or "FSA"?
"fast" is the more common of the two: it sits at frequency rank #767 in our English list, against #24,161 for "FSA". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list