fool around
phrasal verbfool around 
- (British English also fool about)to waste time instead of doing something that you should be doing闲耍;虚度光阴 
- fool around (with somebody) to have a sexual relationship with another person’s partner; to have a sexual relationship with somebody who is not your partner(和某人)乱搞男女关系 - She's been fooling around with a married man.她一直和一个有妇之夫鬼混。 
 
- She's been fooling around with a married man.