muck about vs mess around

muck about and mess around both are verbs.

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

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

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

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

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