English Reference
adjective

arbitrary

adj.
US /ˈɑɹbəˌtɹɛɹi/ UK /ˈɑːbɪtɹəɹi/ ar·bi·trary UK spelling arbitraries

  1. 01 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.

    Simple

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

    In context

    The committee's decision to reject the proposal appeared entirely arbitrary, as they failed to provide any clear criteria for their judgment.

  2. 02 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.

    Simple

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

    In context

    The new regulations were criticized as an arbitrary exercise of ministerial power that bypassed the usual parliamentary oversight.

  3. 03 C2 Proficiency TechnicalAcademic 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.

    Simple

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

    In context

    Saussure argued that the relationship between the signifier and the signified is fundamentally arbitrary, governed only by social convention.

  4. 04 C1 Advanced TechnicalAcademic 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.

    Simple

    Let x be an arbitrary integer in the following equation.

    In context

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

This is especially so, given that bosses can decide where their employees work based on fairly arbitrary reasons.

Phys.org· 18 Aug 2026

Historically, scientists have viewed the cosmos as akin to a rock—complex, perhaps even beautiful, but formed through arbitrary events.

Smithsonian Magazine· 18 Aug 2026

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”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin arbitrārius
Level C1 · Advanced
Frequency Frequent
Updated