únicavsuniríaWhich spelling fits?

Quick tell: única is a adjective, uniría is a verb, so they fill different roles in a sentence.

Which to use

“única” is an adjective and “uniría” is a verb - they look or sound alike but fill different roles in a sentence.

#599
“única” frequency rank
#39,004
“uniría” frequency rank
39603
confusion score

Side-by-Side Comparison

Feature única uniría
Definition Forma del femenino singular de único. Primera persona del singular (yo) del condicional de unir o de unirse.

Where the eye mixes única and uniría

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence. única runs 5 letters (VCVCV) against uniría's 6 (VCVCVV) - the length gap alone is often enough to separate them once you know to check it.

5 ch
única
6 ch
uniría

Why the eye confuses única with uniría

These two trip readers on the page rather than in the ear: única is [ˈunika] while uniría is [uniˈɾia]. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (adjective vs verb), which is usually the fastest check. Our composite confusion score for this pair is 39603, derived from the frequency rank of both members and their visual similarity.

única is recorded at frequency rank #599, classified as anadj, pronounced [ˈunika]. uniría is at rank #39,004, tagged as averb, pronounced [uniˈɾia].

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 39603, this pair ranks #163,634 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of única vs uniría

Shared letters: ain. Private to "única": cú. Private to "uniría": ruí.

"única" · 5 letters · shape VCVCV  ·  "uniría" · 6 letters · shape VCVCVV

Frequently Asked Questions

Is swapping "única" for "uniría" ever safe?
No - they are not even the same part of speech. "única" is an adjective and "uniría" a verb, so a sentence built for one is usually ungrammatical with the other.
In ordinary Spanish text, does "única" or "uniría" show up more?
"única" is the more common of the two: it sits at frequency rank #599 in our Spanish list, against #39,004 for "uniría". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

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

  • Full dictionary entry for "única" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "uniría" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #163,634 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "única" and "uniría" also get mixed up with nearby pairs, the highest-scored neighbour is "umbría vs uniría". Nearby pair

Confusion rank #163,634 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