prevent vs defend

prevent and defend both are verbs.

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

As verbs, defend is a hyponym of prevent; that is, defend is a word with a more specific, narrower meaning than prevent:

prevent: stop (someone or something) from doing something or being in a certain state
defend: be on the defensive; act against an attack

prevent (verb)	defend (verb)
stop (someone or something) from doing something or being in a certain state	argue or speak in defense of
keep from happening or arising; make impossible	state or assert
	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