mess around vs muck around

mess around and muck around both are verbs.

Word	Noun	Adjective	Verb	Adverb
mess around	No	No	Yes	No
muck around	No	No	Yes	No

As verbs, mess around and muck around are synonyms defined as:

mess around and muck around: do random, unplanned work or activities or spend time idly

Other synonyms of mess around include monkey, monkey around, muck about, potter, putter, tinker.

mess around (verb)	muck around (verb)
do random, unplanned work or activities or spend time idly	do random, unplanned work or activities or spend time idly