combat vs fight

combat and fight both are nouns.

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

As nouns, fight is a hypernym of combat; that is, fight is a word with a broader meaning than combat:

Other hypernyms of combat include battle, conflict, engagement.

As nouns, combat and fight are synonyms defined as:

Other synonyms of combat include fighting, scrap.

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

Other hypernyms of combat include contend, struggle.

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

combat (verb)	fight (verb)
battle or contend against in or as if in a battle	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