Synonyms for Abstainer:

n.

abstainer (noun)
ascetic, nondrinker, abstinent.
person (noun)
ascetic.
teetotaler (noun)
prohibitionist, one who is on the wagon, calvinist, member of the WCTU, water-drinker, abstinent, ascetic, teetotalist, puritan, temperance advocate, nondrinker, dry, Bluenose.

Other synonyms:

prohibitionist. nondrinker
nondrinker.
Other relevant words:
calvinist, prohibitionist, puritan, dry, temperance advocate, water-drinker, Bluenose, teetotalist, abstinent, one who is on the wagon.