efficacity
"efficacity" is a 10-letter English headword indexed on PlainSpell.
The verdict
“efficacity” is outside the top-ranked English vocabulary, used as a noun - the kind of word writers most often double-check.
- Unranked
- below top-frequency English
- 10
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Efficacy.
| Property | Value |
|---|---|
| Headword | efficacity |
| Language | English |
| Part of speech | Noun |
| Letters | 10 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “efficacity” sits in English frequency
Spelling & Dictionary Insight
The English entry for efficacity is 10 letters long, classified as a noun. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. The dominant gloss from Wiktionary reads: "Efficacy.".
efficacity has no tracked misspelling variants, since its letter pattern doesn't lend itself to common typo substitutions. This entry stands alone in our confusable dataset, since its spelling is unusual enough that it doesn't cluster with a lookalike.
Etymologically, the entry records: From Middle French efficacité. The correct English form is efficacity, spelled E-F-F-I-C-A-C-I-T-Y.
Definition
- 1Efficacy.
Etymology
From Middle French efficacité.
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “efficacity”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is E-F-F-I-C-A-C-I-T-Y - every other letter order is a misspelling in standard orthography.
- Browse more English words and confusable pairs in the same reference. English words
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.