set out vs plunge

set out is not a noun while plunge is a noun.

Word	Noun	Adjective	Verb	Adverb
set out	No	No	Yes	No
plunge	Yes	No	Yes	No

As verbs, plunge is a hyponym of set out; that is, plunge is a word with a more specific, narrower meaning than set out:

set out (noun)	plunge (noun)
	a brief swim in water
	a steep and rapid fall

set out (verb)	plunge (verb)
take the first step or steps in carrying out an action	begin with vigor
lay out orderly or logically in a line or as if in a line	devote (oneself) fully to
depart for someplace	cause to be immersed
	immerse briefly into a liquid so as to wet, coat, or saturate
	thrust or throw into
	fall abruptly
	drop steeply
	dash violently or with great speed or impetuosity