Which to use
“ISF” is a name and “iss” is a verb - they look or sound alike but fill different roles in a sentence.
- #17,462
- “ISF” frequency rank
- #22,303
- “iss” frequency rank
- 39765
- confusion score
Side-by-Side Comparison
| Feature | ISF | iss |
|---|---|---|
| Definition | Impôt déclaratif payé par les personnes physiques, célibataires ou en couple, possédant un patrimoine imposable dont la valeur nette est supérieure à un seuil fixé par la loi. | Deuxième personne du singulier de l’impératif présent de essen. |
Where the eye mixes ISF and iss
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.
Why the eye confuses ISF with iss
These two trip readers on the page rather than in the ear: ISF is \i ɛ.s‿ɛf\ while iss is \ɪs\. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - f in “ISF” becomes s in “iss”, and the parts of speech differ too (name vs verb), which is usually the fastest check. Our composite confusion score for this pair is 39765, derived from the frequency rank of both members and their visual similarity.
ISF is recorded at frequency rank #17,462, classified as aname, pronounced \i ɛ.s‿ɛf\. iss is at rank #22,303, tagged as averb, pronounced \ɪs\.
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 39765, this pair ranks #245,565 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of ISF vs iss
Shared letters: is. Private to "ISF": f. Private to "iss": -.
"ISF" · 3 letters · shape VCC · "iss" · 3 letters · shape VCC
Frequently Asked Questions
Is swapping "ISF" for "iss" ever safe?
Frequency check: "ISF" vs "iss" - which ranks higher?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "ISF" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "iss" - compare definitions side by side with the headword page. Word entry
- This pair ranks #245,565 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "ISF" and "iss" also get mixed up with nearby pairs, the highest-scored neighbour is "isi vs iss". Nearby pair
Confusion rank #245,565 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.