The Collaborative International Dictionary of English v.0.48:

Abstention \Ab*sten"tion\, a. [F. See Abstain.]
   The act of abstaining; a holding aloof. --Jer. Taylor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

abstention
    n 1: the trait of abstaining (especially from alcohol) [syn:
         abstinence, abstention]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "abstention":
   Encratism, Friday, Lenten fare, Pythagoreanism, Pythagorism,
   Rechabitism, Shakerism, Spartan fare, Stoicism, abstainment,
   abstemiousness, abstinence, anythingarianism, asceticism,
   avoidance, banyan day, celibacy, chastity, continence, cop-out,
   desuetude, disuse, eschewal, evasion, fast, fence-sitting,
   fish day, fruitarianism, gymnosophy, impartiality, independence,
   mugwumpery, mugwumpism, nephalism, neutralism, neutrality,
   nonalignment, noncommitment, nonemployment, noninvolvement,
   nonpartisanism, nonprevalence, nonuse, nothingarianism,
   obsolescence, obsoleteness, obsoletion, obsoletism, pensioning off,
   plain living, refraining, refrainment, retirement,
   sexual abstinence, simple diet, spare diet, strict neutrality,
   superannuation, teetotalism, the pledge, total abstinence,
   unprevalence, vegetarianism



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ABSTENTION, French law. This is the tacit renunciation by an heir of a
succession Merl. Rep. h.t.