abstentious vs abstinent

abstentious is not a noun while abstinent is a noun.

Word	Noun	Adjective	Verb	Adverb
abstentious	No	Yes	No	No
abstinent	Yes	Yes	No	No

As adjectives, abstentious and abstinent are synonyms defined as:

abstentious and abstinent: self-restraining; not indulging an appetite especially for food or drink

abstentious (noun)	abstinent (noun)
	a person who refrains from drinking intoxicating beverages

abstentious (adjective)	abstinent (adjective)
self-restraining; not indulging an appetite especially for food or drink	self-restraining; not indulging an appetite especially for food or drink