[ ahr-bi-trer-ee ]
/ ˈɑr bɪˌtrɛr i /


subject to individual will or judgment without restriction; contingent solely upon one's discretion: an arbitrary decision.
decided by a judge or arbiter rather than by a law or statute.
having unlimited power; uncontrolled or unrestricted by law; despotic; tyrannical: an arbitrary government.
capricious; unreasonable; unsupported: an arbitrary demand for payment.
Mathematics. undetermined; not assigned a specific value: an arbitrary constant.

noun, plural ar·bi·trar·ies.

arbitraries, Printing. (in Britain) peculiar(def 9).

Origin of arbitrary

1400–50; late Middle English < Latin arbitrārius uncertain (i.e., depending on an arbiter's decision). See arbiter, -ary
Related forms Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for unarbitrary


/ (ˈɑːbɪtrərɪ) /


founded on or subject to personal whims, prejudices, etc; capricious
having only relative application or relevance; not absolute
(of a government, ruler, etc) despotic or dictatorial
maths not representing any specific valuean arbitrary constant
law (esp of a penalty or punishment) not laid down by statute; within the court's discretion
Derived Formsarbitrarily, adverbarbitrariness, noun

Word Origin for arbitrary

C15: from Latin arbitrārius arranged through arbitration, uncertain
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for unarbitrary



early 15c., "deciding by one's own discretion," from Old French arbitraire (14c.) or directly from Latin arbitrarius "depending on the will, uncertain," from arbiter (see arbiter). The original meaning gradually descended to "capricious" and "despotic" (1640s). Related: Arbitrarily; arbitrariness.

Online Etymology Dictionary, © 2010 Douglas Harper