Source : Webster's Revised Unabridged Dictionary (1913)

Abstainer \Ab*stain"er\, n.
   One who abstains; esp., one who abstains from the use of
   intoxicating liquors.

Source : WordNet®

abstainer
     n 1: practices self denial as spiritual discipline [syn: {ascetic}]
     2: a person who refrains from drinking intoxicating beverages
        [syn: {abstinent}, {nondrinker}] [ant: {drinker}]