1
general::
Interfere or associate with; also, annoy, bother. For example, Our group won't mess with those street musicians, or I told him not to mess with me or there would be trouble. [Colloquial; c. 1900]
American Heritage Idioms
2
general::
Phrase(s): mess with someone or something [and] monkey with someone or something
to bother or interfere with someone or something. • Come on, don’t monkey with my new camera. • Don’t mess with me unless you want trouble.
McGrawhill's American Idioms And Phrasal Verbs