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arbitrary

/ˈɑːrbɪˌtrɛri/

based on personal whim, not fixed rules

From Latin arbiter (judge).

adjective
noun
arbiter
Latin
AI-inferred
arbiter
a witness, judge, mediator; someone who goes to observe and decide
Latin
Verified
arbitrarius
of arbitration; done by judgment rather than fixed law

from Latin arbitrarius "of arbitration, done by means of arbitration, not regulated by fixed law," hence "depending on...

Middle English
AI-inferred
arbitrarie
borrowed as an adjective for discretionary or judgment-based decisions
Modern English
AI-inferred
arbitrary
shifted from 'discretionary' to 'whimsical, ungrounded, capricious'
Modern English
AI-inferred
arbitrarily
adverb
Modern English
AI-inferred
arbitrariness
noun for the quality of being arbitrary
Modern English
arbitrary

A Roman arbiter was not just a bookish judge in a wig; he was the person who showed up, looked things over, and made a call. Latin turned that courtroom vibe into arbitrarius, a legal word for decisions made by judgment rather than by fixed law. English borrowed it around 1400, and for a while it could sound almost neutral or even official—more like 'discretionary' than 'random.' But once people started talking about arbitrary power, the word took on a harsher edge, as if the judge had wandered off the bench and started making up the rules on the spot. It shares a family with arbitrate and arbitration, so the old meaning of 'settling a dispute' still hums underneath the modern sense of whim. Think of it as a courtroom word that escaped into everyday life carrying a gavel in one hand and a shrug in the other.

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