If you describe something as a fun thing, you mean that you think it is enjoyable. If you describe someone as a fun person, you mean that you enjoy being with them.
It was a fun evening.
那是个令人愉快的夜晚。
You refer to an activity or situation as fun if you think it is pleasant and enjoyable and it causes you to feel happy.
It's been a learning adventure and it's also been great fun.
那是一次很受教育的冒险活动,也非常有意思。
It could be fun to watch them.
看着他们是一种乐趣。
If you say that someone is fun, you mean that you enjoy being with them because they say and do interesting or amusing things.
Liz was fun to be with.
与莉兹相处非常有趣。
for fun
If you do something for fun or for the fun of it, you do it in order to enjoy yourself rather than because it is important or necessary.
We used to drive too fast, just for fun.
我们过去常常高速驾驶,纯粹是为了好玩。
in fun
If you do something in fun, you do it as a joke or for amusement, without intending to cause any harm.
Don't say such things, even in fun.
别说这样的话,即使是闹着玩儿。
make fun of , poke fun at
If you make fun of someone or something or poke fun at them, you laugh at them, tease them, or make jokes about them in a way that causes them to seem ridiculous.
Don't make fun of me.
别拿我开玩笑。