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 Synonym : 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 Synonym : mess somebody around:
The company kept mucking us around and changing the price.

[TahlilGaran] Dictionary of Contemporary English ▲

muck around
muck around (with (something))
to do something without a serious purpose.
Why was she mucking around in such a risky neighborhood?

I kept working on this text until I thought it was good, and then I tried not to muck around with it anymore.

[TahlilGaran] English Idioms Dictionary ▲