fun
Americannoun
verb (used with or without object)
adjective
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Informal. of or relating to fun, especially to social fun.
a fun thing to do; really a fun person; the funnest game.
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Informal. whimsical; flamboyant.
The fashions this year are definitely on the fun side.
idioms
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for / in fun, as a joke; not seriously; playfully.
His insults were only in fun.
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make fun of, to make the object of ridicule; deride.
The youngsters made fun of their teacher.
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like fun, certainly not; of doubtful truth.
He told us that he finished the exam in an hour. Like fun he did!
noun
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a source of enjoyment, amusement, diversion, etc
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pleasure, gaiety, or merriment
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jest or sport (esp in the phrases in or for fun )
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facetious amusement; frivolous activity
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informal
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(adverb) quickly; vigorously
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(interjection) not at all! certainly not!
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to ridicule or deride
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(modifier) full of amusement, diversion, gaiety, etc
a fun sport
verb
Etymology
Origin of fun
First recorded in 1675–85; dialectal variant of obsolete fon “to befool”; see fond 1 ( def. )
Explanation
When you are having fun, you are having a good time. Watching little kids jump around inside an inflatable bouncy house, you can instantly tell how much fun they're having. There is no mistaking fun when you're having it, and it's generally used to mean exactly what it sounds like, some activity or experience that's purely enjoyable. When fun takes the form of an adjective, it's informal, not strictly grammatically correct. So while you can say, "Being with her is so much fun," you can't correctly say, "She is such a fun girl." Fun turns a little bit mean when you're making fun of, or teasing, your friend. In this case, it might be fun for you, but it's probably not very much fun for him.
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.
"Some of these kids might go on to play for England one day - most of them will not - but I hope that the fun they've had here will keep them playing, whatever level."
From BBC • Jun. 10, 2026
Craig Bellamy has tipped Spain or England as teams who could go far, but where is the fun in supporting a favourite?
From BBC • Jun. 10, 2026
It would be a fun year, I’ll say that.”
From Los Angeles Times • Jun. 9, 2026
“It’s fun, but not the kind of thing to play with all day. It’s your money, so it’s serious. But it’s also dynamic and you come back to it when your life evolves.”
From MarketWatch • Jun. 9, 2026
They can indeed be mean, but they are wonderfully self-sufficient and fun to have around even if it takes about thirty of their small eggs to make a decent omelet.
From "Woodsong" by Gary Paulsen
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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.