ENGLISH
REFERENCE

arbitrary

adj.
US //ˈɑɹbəˌtɹɛɹi// UK //ˈɑːbɪtɹəɹi// ar·bi·trary
  1. 1 random or without reason (adj.)
    C1 Advanced Academic

    based on a random choice or a personal whim rather than a logical reason.

    determined by individual discretion or chance rather than by any objective necessity or consistent system.

    Example

    The choice of players for the team seemed completely arbitrary to the fans.

    Example

    The committee's decision to reject the proposal appeared entirely arbitrary, as they failed to provide any clear criteria for their judgment.
  2. 2 unfair use of power (adj.)
    C1 Advanced Formal Law

    using power in an unfair way without considering what is right.

    describing the exercise of power or authority without restraint and regardless of justice or the law.

    Example

    The citizens protested against the arbitrary arrests made by the secret police.

    Example

    The new regulations were criticized as an arbitrary exercise of ministerial power that bypassed the usual parliamentary oversight.
Show 2 more sensesShow fewer
  1. 3 linguistic convention (adj.)
    C2 Proficiency Technical Academic Linguistics

    describing how words have no natural connection to the things they represent.

    referring to the lack of a natural or intrinsic connection between a linguistic signifier and its meaning.

    Example

    The word 'tree' is arbitrary because there is no physical reason why those sounds mean that plant.

    Example

    Saussure argued that the relationship between the signifier and the signified is fundamentally arbitrary, governed only by social convention.
  2. 4 mathematical value (adj.)
    C1 Advanced Technical Academic Math

    representing any value you choose to pick.

    referring to a value or constant that is not specifically determined but can be any member of a set.

    Example

    Let x be an arbitrary integer in the following equation.

    Example

    The proof holds true for an arbitrary value of n, provided that n is a positive real number.
Origin

Etymology tree Latin arbiter Proto-Indo-European *-yósder. Proto-Italic *-āsios Latin -ārius Latin arbitrāriusder. Middle English arbitrarie English arbitrary From Middle English arbitrarie, Latin arbitrārius (“arbitrary, uncertain”), from arbiter (“witness, on-looker, listener, judge, overseer”).

Word family

© 2026 English Reference