arbitrary
Americanadjective
-
subject to individual will or judgment without restriction; contingent solely upon one's discretion.
an arbitrary decision.
-
decided by a judge or arbiter rather than by a law or statute.
-
having unlimited power; uncontrolled or unrestricted by law; despotic; tyrannical.
an arbitrary government.
-
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.
-
Mathematics. undetermined; not assigned a specific value.
an arbitrary constant.
noun
adjective
-
founded on or subject to personal whims, prejudices, etc; capricious
-
having only relative application or relevance; not absolute
-
(of a government, ruler, etc) despotic or dictatorial
-
maths not representing any specific value
an arbitrary constant
-
law (esp of a penalty or punishment) not laid down by statute; within the court's discretion
Other Word Forms
Derived Forms
Inflected Forms
Nouns
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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
100 SAT Words Beginning with "A"
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
The Declaration of Independence
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
And those arbitrary restrictions — they’re OK 24 hours before a match, but not 48? — have put Team Melli at a competitive disadvantage.
From Los Angeles Times • Jun. 22, 2026
He called his arrest an "arbitrary, capricious prosecution".
From BBC • Jun. 21, 2026
It was established as a safeguard against arbitrary and unlawful imprisonment, so if a judge finds the government’s reasoning insufficient, they hold the power to immediately order the prisoner’s release with sufficient legal grounds.
From Slate • Jun. 18, 2026
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
It must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.
From "A Brief History of Time: And Other Essays" by Stephen Hawking
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.
