walk out vs dissent

walk out is not a noun while dissent is a noun.

Word	Noun	Adjective	Verb	Adverb
walk out	No	No	Yes	No
dissent	Yes	No	Yes	No

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

Other hypernyms of walk out include protest, resist.

walk out (noun)	dissent (noun)
	the act of protesting; a public (often organized) manifestation of dissent
	(law) the difference of one judge's opinion from that of the majority
	a difference of opinion

walk out (verb)	dissent (verb)
leave suddenly, often as an expression of disapproval	withhold assent
leave abruptly, often in protest or anger	be of different opinions
stop work in order to press demands	express opposition through action or words