mill vs mill around

mill is a noun but mill around is not a noun.

Word	Noun	Adjective	Verb	Adverb
mill	Yes	No	Yes	No
mill around	No	No	Yes	No

As verbs, mill and mill around are synonyms defined as:

Other synonyms of mill include mill about.

mill (noun)	mill around (noun)
the act of grinding to a powder or dust
machinery that processes materials by grinding or crushing
a plant consisting of one or more buildings with facilities for manufacturing

mill (verb)	mill around (verb)
grind with a mill	move about in a confused manner
produce a ridge around the edge of	be about a place without any apparent purpose
roll out (metal) with a rolling machine
move about in a confused manner