Overview
Fun is defined by the Oxford English Dictionary as "light-hearted pleasure, enjoyment, or amusement; boisterous joviality or merrymaking; entertainment".
Etymology and usage
The word fun is associated with sports, entertaining media, high merriment, and amusement. Although its etymology is uncertain, it has been speculated that it may be derived from Middle English (fool) and (the one fooling the other). An 18th century meaning (still used in Orkney and Shetland) was "cheat, trick, hoax", a meaning still retained in the phrase "to make fun of".
The way the word fun is used demonstrates its distinctive elusiveness and happiness. Expressions such as "Have fun!" and "That was fun!" indicate that fun is pleasant, personal, and to some extent unpredictable. Expressions such as "I was making fun of myself" convey the sense that fun is something that can be amusing and not to be taken seriously. The adjective "funny" has two meanings, which often need to be clarified between a speaker and listener. One meaning is "amusing, jocular, droll" and the other meaning is "odd, quirky, peculiar". These differences indicate the evanescent and experiential nature of fun and the difficulty of distinguishing "fun" from "enjoyment".
Fun's evanescence can be seen when an activity regarded as fun becomes goal-oriented. Many physical activities and individual sports are regarded as fun until the participant seeks to win a competition, at which point, much of the fun may disappear as the individual's focus tightens. Surfing is an example. If you are a "mellow soul" (not in a competition or engaging in extreme sport) "once you're riding waves, you're guaranteed to be having fun".
From Wikipedia (CC BY-SA 4.0).