fight down vs fight back

fight down and fight back both are verbs.

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

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

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

fight down (verb)	fight back (verb)
fight against or resist strongly	fight against or resist strongly
	defend oneself