knock out vs overwhelm

knock out and overwhelm both are verbs.

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

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

Other hypernyms of knock out include overcome, overpower, overtake, sweep over, whelm.

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