overrun vs defeat

overrun and defeat both are nouns.

Word	Noun	Adjective	Verb	Adverb
overrun	Yes	No	Yes	No
defeat	Yes	No	Yes	No

As verbs, defeat is a hypernym of overrun; that is, defeat is a word with a broader meaning than overrun:

Other hypernyms of overrun include get the better of, overcome.

overrun (noun)	defeat (noun)
too much production or more than expected	an unsuccessful ending to a struggle or contest
	the feeling that accompanies an experience of being thwarted in attaining your goals

overrun (verb)	defeat (verb)
run beyond or past	win a victory over
seize the position of and defeat	thwart the passage of
flow or run over (a limit or brim)
invade in great numbers
occupy in large numbers or live on a host