mess around with somebody/something ( also mess about with somebody/something British English ) phrasal verb informal ( see also ↑ mess )
1 . to have a sexual relationship with someone that you should not have a sexual relationship with:
She’d been messing around with another man.
2 . to spend time playing with something, repairing it etc:
Dave likes messing around with old cars.
3 . to use something and make annoying changes to it:
Who’s been messing around with my camera?