contend vs combat

contend is not a noun while combat is a noun.

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

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

contend (noun)	combat (noun)
	an engagement fought between two military forces
	the act of fighting; any contest or struggle

contend (verb)	combat (verb)
to make the subject of dispute, contention, or litigation	battle or contend against in or as if in a battle
have an argument about something
maintain or assert
compete for something; engage in a contest; measure oneself against others
be engaged in a fight; carry on a fight
succeed in doing, achieving, or producing (something) with the limited or inadequate means available