muck about

verb4

1. •
   (informal) To do random unplanned work or spend time idly

   • Stop mucking about and get on with your work!
2. •
   (UK, informal) To be playful; full of fun and high spirits; to treat a situation unseriously.

   • It was only a joke. We were only mucking about.
3. •
   (informal) To attempt to do something with a piece of equipment without understanding how it works.

   • Don't muck about with the video machine, or you might break it.
4. •
   To play with; to toy with; to waste the time of (a person).

   • Then he started stalling. In the end he mucked me about so much that I lost my patience and decided to nick the books from him. — 1955