mess withphrasal verb
Definition of mess with
1 : to cause trouble for (someone) : to deal with (someone) in a way that may cause anger or violence I wouldn't want to mess with him. You'd better not be messing with me.
2 chiefly US : to deal with or be involved with (something that causes or that could cause trouble) The company doesn't want to mess with small distributors. He doesn't want to mess with cocaine anymore.
3 : to handle or play with (something) in a careless way : to mess around with (something) Don't mess with the camera.