arbitrary
Americanadjective
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subject to individual will or judgment without restriction; contingent solely upon one's discretion.
an arbitrary decision.
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decided by a judge or arbiter rather than by a law or statute.
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having unlimited power; uncontrolled or unrestricted by law; despotic; tyrannical.
an arbitrary government.
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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.
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Mathematics. undetermined; not assigned a specific value.
an arbitrary constant.
noun
adjective
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founded on or subject to personal whims, prejudices, etc; capricious
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having only relative application or relevance; not absolute
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(of a government, ruler, etc) despotic or dictatorial
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maths not representing any specific value
an arbitrary constant
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law (esp of a penalty or punishment) not laid down by statute; within the court's discretion
Other Word Forms
Derived Forms
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.
Vocabulary lists containing arbitrary
The Vocabulary.com Top 1000
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100 SAT Words Beginning with "A"
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The Declaration of Independence
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The complaint is being filed on behalf of 14 deportees, some of whom are currently held in Equatorial Guinea under conditions "amounting to arbitrary and indefinite detention", according to the lawsuit, seen by AFP.
From Barron's • Jun. 5, 2026
All this variance and randomness, all these rules on top of regulations, none of it is exactly arbitrary, but neither is it fair.
From Los Angeles Times • May 27, 2026
A Federal Reserve paper published last year found substantial and arbitrary variation in agent commissions across metropolitan areas.
From MarketWatch • May 19, 2026
One place to start is reversing the agency’s arbitrary and callous rejections of rare disease and cancer treatments.
From The Wall Street Journal • May 8, 2026
They were no longer waiting for some arbitrary grade.
From "Beauty Queens" by Libba Bray
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
