swoon vs zonk out

swoon is a noun but zonk out is not a noun.

Word	Noun	Adjective	Verb	Adverb
swoon	Yes	No	Yes	No
zonk out	No	No	Yes	No

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

swoon: pass out from weakness, physical or emotional distress due to a loss of blood supply to the brain
zonk out: lose consciousness due to a sudden trauma, for example

Other hypernyms of swoon include black out, pass out.

swoon (noun)	zonk out (noun)
a spontaneous loss of consciousness caused by insufficient blood to the brain

swoon (verb)	zonk out (verb)
pass out from weakness, physical or emotional distress due to a loss of blood supply to the brain	fall asleep fast, as when one is extremely tired
	lose consciousness due to a sudden trauma, for example