1. subject to individual will or judgment without restriction; contingent solely upon one's discretion: an arbitrary decision.
  2. decided by a judge or arbiter rather than by a law or statute.
  3. having unlimited power; uncontrolled or unrestricted by law; despotic; tyrannical: an arbitrary government.
  4. capricious; unreasonable; unsupported: an arbitrary demand for payment.
  5. Mathematics. undetermined; not assigned a specific value: an arbitrary constant.
noun, plural ar·bi·trar·ies.
  1. 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 formsar·bi·trar·i·ly [ahr-bi-trer-uh-lee, ahr-bi-trair-] /ˈɑr bɪˌtrɛr ə li, ˌɑr bɪˈtrɛər-/, adverbar·bi·trar·i·ness, nounnon·ar·bi·trar·i·ly, adverbnon·ar·bi·trar·i·ness, nounnon·ar·bi·trar·y, adjectiveun·ar·bi·trar·i·ly, adverbun·ar·bi·trar·y, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for arbitraries


  1. founded on or subject to personal whims, prejudices, etc; capricious
  2. having only relative application or relevance; not absolute
  3. (of a government, ruler, etc) despotic or dictatorial
  4. maths not representing any specific valuean arbitrary constant
  5. 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 arbitraries



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