arbitrary

American  

[ahr-bi-trer-ee] / ˈɑr bɪˌtrɛr i /

adjective

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. based on whim or personal preference, without reason or pattern; random.

   This is an unusual encyclopedia, arranged by topics in a more or less arbitrary order.

5. Mathematics. undetermined; not assigned a specific value.

   an arbitrary constant.

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noun

• arbitraries
  plural

1. Printing. arbitraries, (in Britain) peculiar.

arbitrary British  

/ ˈɑːbɪtrərɪ /

adjective

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 value

   an arbitrary constant

5. law (esp of a penalty or punishment) not laid down by statute; within the court's discretion

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Other Word Forms

Derived Forms

• arbitrariness
  noun
• nonarbitrary
  adjective
• unarbitrary
  adjective
• arbitrarily
  adverb

Inflected Forms

Nouns

• arbitraries
  plural

Etymology

Origin of arbitrary

First recorded in 1400–50; late Middle English, from Latin arbitrārius “uncertain” (i.e., depending on an arbiter's decision); see origin at arbiter, -ary

Explanation

Something that's arbitrary seems like it's chosen at random instead of following a consistent rule. Team members would dislike their coach using a totally arbitrary method to pick starting players. Even though arbitrary comes from a word meaning "judge" (arbiter), that doesn't mean judges are always fair. Calling a decision-maker arbitrary is usually a negative thing, suggesting the person is making rules based on whim rather than justice. A coach who selects starting players arbitrarily isn't strictly applying a rule; he could just be picking names out of a hat.

Example Sentences

See Examples For:

arbitrary arbitraries

One of those displaced by the advance was Jamal Abu Miri, a 68-year-old retired land surveyor who understood firsthand that the Yellow Line was more than just an arbitrary marker on a map.

From Los Angeles Times ● Aug. 9, 2026

In a legal document seen by the BBC, the coalition of Democratic states said the decision was "arbitrary, capricious, and contrary to law."

From BBC ● Aug. 4, 2026

It has a liberal side—secure property rights, courts that constrain the state—that shields entrepreneurs from arbitrary state power, ranging from selective prosecution to outright expropriation.

From The Wall Street Journal ● Jul. 31, 2026

Pitman’s finding that the process is arbitrary is really a finding that the number doesn’t mean what the state says it means.

From Slate ● Jul. 31, 2026

In contrast, Bill’s reasoning started from the seemingly arbitrary hypothesis that only a fraction of the male chromosomal material enters the female cell.

From "Double Helix" by James D. Watson

Some contained codes, devised by Anson Stager, general manager of U.S. military telegraphs, that inserted decoy words or arbitraries into messages that were unscrambled with cipher charts.

From Los Angeles Times ● Aug. 19, 2016

Related Words

• capricious
• discretionary
• erratic
• frivolous
• inconsistent
• irrational
• irresponsible
• random
• subjective
• unreasonable
• willful