repulse vs defend

repulse is a noun but defend is not a noun.

Word	Noun	Adjective	Verb	Adverb
repulse	Yes	No	Yes	No
defend	No	No	Yes	No

As verbs, defend is a hypernym of repulse; that is, defend is a word with a broader meaning than repulse:

Other hypernyms of repulse include fight, fight back, fight down, oppose.

repulse (noun)	defend (noun)
an instance of driving away or warding off

repulse (verb)	defend (verb)
force or drive back	argue or speak in defense of
cause to move back by force or influence	state or assert
be repellent to; cause aversion in	be on the defensive; act against an attack
	protect against a challenge or attack
	protect or fight for as a champion
	fight against or resist strongly
	be the defense counsel for someone in a trial