To dawdle or fritter (something) away
To tinker is defined as to play around with something, or to try to change or fix it.
To play, fiddle, trifle, or tamper with something:
(Idiomatic) To act foolishly.
do random, unplanned work or activities or spend time idly
Find another word for muck-around. In this page you can discover 7 synonyms, antonyms, idiomatic expressions, and related words for muck-around, like: putter, mess around, potter, tinker, monkey, monkey-around and muck-about.