teetotaller vs abstainer

teetotaller and abstainer both are nouns.

Word	Noun	Adjective	Verb	Adverb
teetotaller	Yes	No	No	No
abstainer	Yes	No	No	No

As nouns, abstainer is a hypernym of teetotaller; that is, abstainer is a word with a broader meaning than teetotaller:

Other hypernyms of teetotaller include abstinent, nondrinker.

teetotaller (noun)	abstainer (noun)
a total abstainer	a person who refrains from drinking intoxicating beverages
	someone who practices self denial as a spiritual discipline