overwhelm vs knock out

overwhelm and knock out both are verbs.

Word	Noun	Adjective	Verb	Adverb
overwhelm	No	No	Yes	No
knock out	No	No	Yes	No

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

Other hyponyms of overwhelm include devastate, clutch, get hold of, seize, kill, benight, stagger, lock.

overwhelm (verb)	knock out (verb)
charge someone with too many tasks	destroy or break forcefully
overcome by superior force	eliminate
cover completely or make imperceptible	empty (as of tobacco) by knocking out
overcome, as with emotions or perceptual stimuli	knock unconscious or senseless
	overwhelm with admiration