joke/ ʤəuk /

1.noun [c] 
(funny story) 笑话

2.noun
(prank) 玩笑

3.vi.
开玩笑

the decision was a joke
 [inf] 这个决定真是荒唐
it's no joke
 [inf] 不是闹着玩儿的
to play a joke on sb
开某人的玩笑
to joke about sth
以某事为笑柄
you're joking (or) you must be joking!
 [inf] 你在开玩笑{或}你一定在开玩笑吧!