isivsistTell them apart

Quick tell: isi is a noun, ist is a verb, so they fill different roles in a sentence.

Which to use

“isi” is a noun and “ist” is a verb - they look or sound alike but fill different roles in a sentence.

#39,822
“isi” frequency rank
#41,994
“ist” frequency rank
81816
confusion score

Side-by-Side Comparison

Feature isi ist
Definition El extranjero, tierra o país de donde uno no es. Tercera persona del singular (er, sie, es) del presente de indicativo de sein.

Where the eye mixes isi and ist

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence. isi (VCV) and ist (VCC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.

3 ch
isi
3 ch
ist

Why the eye confuses isi with ist

These two trip readers on the page rather than in the ear: isi is /ì.sí/ while ist is /ɪst/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - i in “isi” becomes t in “ist”, and the parts of speech differ too (noun vs verb), which is usually the fastest check. Our composite confusion score for this pair is 81816, derived from the frequency rank of both members and their visual similarity.

isi is recorded at frequency rank #39,822, classified as anoun, pronounced /ì.sí/. ist is at rank #41,994, tagged as averb, pronounced /ɪst/.

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 81816, this pair ranks #9,948 of 323,831 scored Spanish confusable pairs - among the most confusable pairs.

Orthographic DNA of isi vs ist

Shared letters: is. Private to "isi": -. Private to "ist": t.

"isi" · 3 letters · shape VCV  ·  "ist" · 3 letters · shape VCC

Frequently Asked Questions

Can "isi" and "ist" be used interchangeably?
No - they are not even the same part of speech. "isi" is a noun and "ist" a verb, so a sentence built for one is usually ungrammatical with the other.
In ordinary Spanish text, does "isi" or "ist" show up more?
"isi" is the more common of the two: it sits at frequency rank #39,822 in our Spanish list, against #41,994 for "ist". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "isi" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "ist" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #9,948 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "isi" and "ist" also get mixed up with nearby pairs, the highest-scored neighbour is "ist vs iza". Nearby pair

Confusion rank #9,948 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list