combat vs encounter

combat and encounter both are nouns.

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

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

combat (noun)	encounter (noun)
an engagement fought between two military forces	a minor short-term fight
the act of fighting; any contest or struggle	a casual meeting with a person or thing
	a hostile disagreement face-to-face
	a casual or unexpected convergence

combat (verb)	encounter (verb)
battle or contend against in or as if in a battle	contend against an opponent in a sport, game, or battle
	come together
	come upon, as if by accident; meet with
	be beset by
	experience as a reaction