walk around vs act

walk around is not a noun while act is a noun.

Word	Noun	Adjective	Verb	Adverb
walk around	No	No	Yes	No
act	Yes	No	Yes	No

As verbs, act is a hypernym of walk around; that is, act is a word with a broader meaning than walk around:

walk around: behave in a certain manner or have certain properties
act: behave in a certain manner; show a certain behavior; conduct or comport oneself

Other hypernyms of walk around include acquit, bear, behave, carry, comport, conduct, deport, do.

As verbs, act is a hypernym of walk around; that is, act is a word with a broader meaning than walk around:

Other hypernyms of walk around include move.

walk around (noun)	act (noun)
	something that people do or cause to happen
	a subdivision of a play or opera or ballet
	a legal document codifying the result of deliberations of a committee or society or legislative body
	a short performance that is part of a longer program
	a manifestation of insincerity

walk around (verb)	act (verb)
walk with no particular goal	behave in a certain manner; show a certain behavior; conduct or comport oneself
walk around something	pretend to have certain qualities or state of mind
behave in a certain manner or have certain properties	discharge one's duties
walk randomly	play a role or part
	perform on a stage or theater
	behave unnaturally or affectedly
	perform an action, or work out or perform (an action)
	have an effect or outcome; often the one desired or expected
	be suitable for theatrical performance