fight off vs fight

fight off is not a noun while fight is a noun.

Word	Noun	Adjective	Verb	Adverb
fight off	No	No	Yes	No
fight	Yes	No	Yes	No

As verbs, fight is a hypernym of fight off; that is, fight is a word with a broader meaning than fight off:

Other hypernyms of fight off include defend, fight back, fight down, oppose.

fight off (noun)	fight (noun)
	a hostile meeting of opposing military forces in the course of a war
	the act of fighting; any contest or struggle
	a boxing or wrestling match
	an aggressive willingness to compete
	an intense verbal dispute

fight off (verb)	fight (verb)
force or drive back	be engaged in a fight; carry on a fight
	fight against or resist strongly
	make a strenuous or labored effort
	exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for