"The kids sat there messing around with leaves and blades of grass because they were bored.; These guys don't mess around! They finished the whole job in ten minutes."
2.VerbTo joke, kid, or play.
"Hey, don't take it personally. I was only messing around.; Don't mess around with electricity if you don't understand it."
3.VerbTo have a sexual relationship, especially one which is non-commital.
"Rumor has it that he's messing around with his secretary."