Which to use
“fei” is a particle and “FSB” is a noun - they look or sound alike but fill different roles in a sentence.
- #21,248
- “fei” frequency rank
- #41,175
- “FSB” frequency rank
- 62423
- confusion score
Side-by-Side Comparison
| Feature | fei | FSB |
|---|---|---|
| Definition | erzgebirgisch, fränkisch, süddeutsch, oberdeutsch, drückt aus, dass man annimmt, dass die oder der Angesprochene das Gesagte noch nicht weiß | russischer Inlandsgeheimdienst und Geheimpolizei |
Where the eye mixes fei and FSB
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Visual trap between fei and FSB
These two trip readers on the page rather than in the ear: fei is [faɪ̯] while FSB is [ɛfʔɛsˈbeː]. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (particle vs noun), which is usually the fastest check. Our composite confusion score for this pair is 62423, derived from the frequency rank of both members and their visual similarity.
fei is recorded at frequency rank #21,248, classified as aparticle, pronounced [faɪ̯]. FSB is at rank #41,175, tagged as anoun, pronounced [ɛfʔɛsˈbeː].
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 62423, this pair ranks #713,425 of 2,006,359 scored German confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fei vs FSB
Shared letters: f. Private to "fei": ei. Private to "FSB": bs.
"fei" · 3 letters · shape CVV · "FSB" · 3 letters · shape CCC
Frequently Asked Questions
Do "fei" and "FSB" mean the same thing in a sentence?
In ordinary German text, does "fei" or "FSB" show up more?
Useful next steps
Eye-level mix-up between "fei" and "FSB" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "fei" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "FSB" - compare definitions side by side with the headword page. Word entry
- This pair ranks #713,425 of 2,006,359 scored German confusable pairs in this corpus vintage. Corpus statistics
- "fei" and "FSB" also get mixed up with nearby pairs, the highest-scored neighbour is "fist vs FSB". Nearby pair
Confusion rank #713,425 of 2,006,359 scored German pairs, corpus vintage 2026-09-03, not spelling advice.