The noun fun has 4 senses (first 3 from tagged texts)
1. (9) fun, merriment, playfulness -- (activities that are enjoyable or amusing; "I do it for the fun of it"; "he is fun to have around")
2. (3) fun, play, sport -- (verbal wit or mockery (often at another's expense but not to be taken seriously); "he became a figure of fun"; "he said it in sport")
3. (1) fun -- (violent and excited activity; "she asked for money and then the fun began"; "they began to fight like fun")
4. playfulness, fun -- (a disposition to find (or make) causes for amusement; "her playfulness surprised me"; "he was fun to be with")
Overview of adj fun
The adj fun has 1 sense (first 1 from tagged texts)
1. (6) amusing, amusive, diverting, fun -- (providing enjoyment; pleasantly entertaining; "an amusing speaker"; "a diverting story"; "a fun thing to do")