Unreasonability

Part of speech: noun

Definitions

1. The quality of acting, thinking or demanding things in a way that goes beyond what is fair, sensible or justified
2. The trait of being stubborn, excessive or illogical in one's behavior, requests or judgments without good cause
3. Behavior or demands that lack reason or fairness, marked by a refusal to accept sensible limits or arguments

Etymology: Unreasonability is a plain formation built from "unreason" and "-ability," and its history runs back to Middle English. The noun first appeared in the form "unresonabiltee" or "unresonabylite," which shows the word was being assembled from parts that English already used: "unreasonable" (not reasonable) plus the suffix "-ability," which turns an adjective into a noun for the quality it describes. So the word means, quite literally, the state of being unreasonable. The "-ability" suffix was itself borrowed through French from Latin "-abilitas," and it attached freely to English adjectives over the centuries. Because "unreasonable" was already well established, speakers could simply add the suffix when they needed a noun for the quality, and the result was a word whose meaning could be read straight off its parts.

Synonyms: unreasonableness, irrationality

Antonyms: reasonableness, rationality