muck around vs mess around

muck around and mess around both are verbs.

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

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

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

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

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