loiter vs mess about

loiter and mess about both are verbs.

Word	Noun	Adjective	Verb	Adverb
loiter	No	No	Yes	No
mess about	No	No	Yes	No

As verbs, loiter and mess about are synonyms defined as:

Other synonyms of loiter include footle, hang around, lallygag, linger, loaf, lollygag, lounge, lurk, mill about, mill around, tarry.

loiter (verb)	mess about (verb)
be about a place without any apparent purpose	be about a place without any apparent purpose