fool around with

phrase

variants or chiefly British fool about with

1

: to use or do (something) in a way that is not very serious

I'm not really a painter; I just like to fool around with paints.

2

: to handle or interact with (something) in a careless or foolish way : to meddle, tamper, or experiment with (something) especially thoughtlessly or ignorantly

Don't fool around with that drill.

3

: to have sex with (someone who is not one's spouse or regular partner)

His partner discovered that he was fooling around with his co-worker.

Word History

First Known Use

1923, in the meaning defined at sense 3