contentious vs contention

contentious is not a noun while contention is a noun.

Word	Noun	Adjective	Verb	Adverb
contentious	No	Yes	No	No
contention	Yes	No	No	No

contentious (noun)	contention (noun)
	the act of competing as for profit or a prize
	a contentious speech act; a dispute where there is strong disagreement
	a point asserted as part of an argument

contentious (adjective)	contention (adjective)
inclined or showing an inclination to dispute or disagree, even to engage in law suits
involving or likely to cause controversy