adj
Common
arbitrary
AH-bih-truh-ree
Arbitrary (adj) means Based on personal choice or chance rather than any clear reason, rule, or system. Example: “The teacher's marking seemed arbitrary, with similar answers receiving very different grades.”
adj
1
Based on personal choice or chance rather than any clear reason, rule, or system.
"The teacher's marking seemed arbitrary, with similar answers receiving very different grades."
"The rule felt completely arbitrary — nobody could explain why it existed."
"They picked a seemingly arbitrary cutoff date for applications."
2
Used, in mathematics and logic, to mean "any one you like" out of all the possibilities — not random in the everyday sense, but unspecified.
"Choose an arbitrary point on the circle and draw a line through it."
"The proof works for an arbitrary triangle, not just a special case."
"Let n be an arbitrary positive integer."
How to use arbitrary
Learner’s notesIn plain EnglishDecided without a clear reason, or (in maths) simply "any given one".
Common mistake
In everyday use "arbitrary" often carries a negative sense of "unfair" or "unjustified"; in maths and logic it's neutral, just meaning "unspecified".
Common pairings
arbitrary decision
arbitrary rule
seemingly arbitrary
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Word forms
- Plural
- arbitraries
- Comparative
- more arbitrary
- Superlative
- most arbitrary
Fill the gap
Can you complete this real example?
The teacher's marking seemed _____, with similar answers receiving very different grades.
Etymology
From Latin arbitrarius, "uncertain, subject to a judge's discretion", from arbiter, "judge".
Synonyms
View more →Antonyms
nonarbitrary
Related words
Rhymes for arbitrary
See all rhymes for arbitrary →Frequently asked questions
What does “arbitrary” mean?
The word “arbitrary” means based on personal choice or chance rather than any clear reason, rule, or system. In plain terms, decided without a clear reason, or (in maths) simply "any given one".
How do you pronounce “arbitrary”?
“Arbitrary” is pronounced AH-bih-truh-ree (/ˈɑɹ.bɪˌtɹɛ(ə).ɹi/ in IPA).
How do you use “arbitrary” in a sentence?
Here is “arbitrary” used in a sentence: “The rule felt completely arbitrary — nobody could explain why it existed.”
What part of speech is “arbitrary”?
“Arbitrary” is an adjective.
Where does the word “arbitrary” come from?
The word “arbitrary” comes from Latin. From Latin arbitrarius, "uncertain, subject to a judge's discretion", from arbiter, "judge".
Is “arbitrary” a common word?
“Arbitrary” is a fairly common word in modern English.
How many meanings does “arbitrary” have?
“Arbitrary” has 2 distinct senses listed in this dictionary. The most common is: based on personal choice or chance rather than any clear reason, rule, or system.
What is the difference between arbitrary and random?
Arbitrary describes a decision made by personal choice or whim without a clear justifying rule, while random specifically implies no pattern or predictability at all, often in a statistical or chance-based sense. An arbitrary decision can still be made deliberately by a person, whereas something random happens without deliberate control.
What does arbitrary mean in mathematics?
In mathematics and logic, arbitrary means "any one you like" out of all the possible options, rather than random in the everyday sense. For example, an "arbitrary constant" refers to an unspecified value that could be any number, not one chosen by chance.
Is calling a decision arbitrary a criticism?
Yes, describing a decision, rule, or punishment as arbitrary is usually critical, implying it lacks a fair or clear justification and was based on personal whim rather than reasoned judgment. It is commonly used in legal and political contexts to challenge the fairness of a ruling or policy.
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