infecciónvsinfecciosaWhich spelling fits?

Quick tell: infección is a noun, infecciosa is an adjective, so they fill different roles in a sentence.

Which to use

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

#6,547
“infección” frequency rank
#39,813
“infecciosa” frequency rank
46360
confusion score

Side-by-Side Comparison

Feature infección infecciosa
Definition Acción o efecto de infectar o de infectarse. Forma del femenino de infeccioso.

Where the eye mixes infección and infecciosa

Muted = shared; highlighted = the visual trap. They share 7 letters in sequence. infección runs 9 letters (VCCVCCVVC) against infecciosa's 10 (VCCVCCVVCV) - the length gap alone is often enough to separate them once you know to check it.

9 ch
infección
10 ch
infecciosa

Visual trap between infección and infecciosa

These two trip readers on the page rather than in the ear: infección is [ĩɱfekˈsjõn] while infecciosa is [ĩɱfekˈsjosa]. 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 (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 46360, derived from the frequency rank of both members and their visual similarity.

infección is recorded at frequency rank #6,547, classified as anoun, pronounced [ĩɱfekˈsjõn]. infecciosa is at rank #39,813, tagged as anadj, pronounced [ĩɱfekˈsjosa].

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 46360, this pair ranks #126,179 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of infección vs infecciosa

Shared letters: cefin. Private to "infección": ó. Private to "infecciosa": aos.

"infección" · 9 letters · shape VCCVCCVVC  ·  "infecciosa" · 10 letters · shape VCCVCCVVCV

Known mistypes of this pair

  • infecciosa ← ifnecciosa · inefcciosa · infceciosa · infeccioas · infeccisoa · infeccoisa · infecicosa · infeciosa

Frequently Asked Questions

Do "infección" and "infecciosa" mean the same thing in a sentence?
No - they are not even the same part of speech. "infección" is a noun and "infecciosa" an adjective, so a sentence built for one is usually ungrammatical with the other.
In ordinary Spanish text, does "infección" or "infecciosa" show up more?
"infección" is the more common of the two: it sits at frequency rank #6,547 in our Spanish list, against #39,813 for "infecciosa". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Eye-level mix-up between "infección" and "infecciosa" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "infección" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "infecciosa" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #126,179 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "infección" and "infecciosa" also get mixed up with nearby pairs, the highest-scored neighbour is "infecciosa vs infecciosas". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #126,179 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