reasonability

noun

"reasonability" is a 13-letter English headword indexed on PlainSpell.

The verdict

“reasonability” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
13
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The state or quality of being reasonable.

Corpus desk

Index EN-reasonability · reasonability · English

reasonability · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 13 letters
  • VOW-7 7 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "R" thin
  • PHOTO-UNK Peer pending

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Key facts for reasonability
PropertyValue
Headwordreasonability
LanguageEnglish
Part of speechNoun
Letters13
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “reasonability” in English

reasonabilitysits beyond the 100,000 most-frequent English words, in the long tail of technical, archaic, or otherwise rare vocabulary where spelling doubt tends to strike hardest.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

reasonability is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "The state or quality of being reasonable.".

reasonability has no tracked misspelling variants, since its letter sequence doesn't invite the usual edit-distance slips. Our dataset records no confusable match here, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

Etymologically, the entry records: From reason(able) + -ability. Compare Middle English unresonabiltee, unresonabylite, whence unreasonability. Piecewise doublet of rationability. The correct English form is reasonability, spelled R-E-A-S-O-N-A-B-I-L-I-T-Y.

Definition

  1. 1
    The state or quality of being reasonable.

Recorded use

Wiktionary examples

These source excerpts show how reasonability appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. 1897, Judson Harmon, "Brief for the United States in the Case of the United States of America v. The Trans-Missouri Freight Association," The Yale Law Journal, vol. 6, no. 6, p. 323n., The very difficult inquiry as to the reasonability of such agreements was an inadequate protection.
  2. Epistemic reasonability could be understood in terms of the general requirement to try to have the largest possible set of logically independent beliefs that is such that the true beliefs outnumber the false beliefs.

Etymology

From reason(able) + -ability. Compare Middle English unresonabiltee, unresonabylite, whence unreasonability. Piecewise doublet of rationability.

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

How do you spell "reasonability"?
"reasonability" is spelled R-E-A-S-O-N-A-B-I-L-I-T-Y.
What does "reasonability" mean?
As a noun, "reasonability" means: The state or quality of being reasonable.
What is the origin of the word "reasonability"?
From reason(able) + -ability. Compare Middle English unresonabiltee, unresonabylite, whence unreasonability. Piecewise doublet of rationability. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

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

Source: FrequencyWords open word-frequency list