Meaning

• To do random unplanned work or spend time idly

  "Stop mucking about and get on with your work!"

• 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."

• To be playful; full of fun and high spirits; to not treat the situation seriously.

  "It was only a joke. We were only mucking about."