muck about/around phrasal verb British English informal ( see also ↑ muck )
1 . to behave in a silly way, especially when you should be working or paying attention to something SYN mess around :
Stop mucking about and listen!
Some of the boys were mucking around on bikes.
2 . muck somebody about/around to cause trouble for someone, especially by changing your mind a lot or not doing what you promised to do SYN mess somebody around :
The company kept mucking us around and changing the price.