fight down vs defend

fight down and defend both are verbs.

Word	Noun	Adjective	Verb	Adverb
fight down	No	No	Yes	No
defend	No	No	Yes	No

As verbs, fight down and defend are synonyms defined as:

Other synonyms of fight down include fight, fight back, oppose.

fight down (verb)	defend (verb)
fight against or resist strongly	argue or speak in defense of
	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