From The Collaborative International Dictionary of English v.0.48 :
Teetotaler \Tee*to"tal*er\, n.
One pledged to entire abstinence from all intoxicating
drinks.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
teetotaler
n 1: a total abstainer [syn: teetotaler, teetotaller,
teetotalist]
From The Devil's Dictionary (1881-1906) :
TEETOTALER, n. One who abstains from strong drink, sometimes totally, sometimes tolerably totally.