The Collaborative International Dictionary of English v.0.48:

Self-control \Self`-con*trol"\, n.
   Control of one's self; restraint exercised over one's self;
   self-command.
   [1913 Webster]

WordNet (r) 3.0 (2006):

self-control
    n 1: the act of denying yourself; controlling your impulses
         [syn: self-denial, self-discipline, self-control]
    2: the trait of resolutely controlling your own behavior [syn:
       self-control, self-possession, possession, willpower,
       will power, self-command, self-will]

Moby Thesaurus II by Grady Ward, 1.0:

143 Moby Thesaurus words for "self-control":
   abnegation, abstinence, acceptance, aplomb, arrest, arrestation,
   assurance, balance, calm, calmness, check, composure, confidence,
   conservatism, constancy, constraint, continence, control, cool,
   cooling, cooling down, cooling off, coolness, curb, curtailment,
   deceleration, denial, determination, dignity, discipline,
   dispassion, doggedness, endurance, equability, equanimity,
   equilibrium, even temper, evenness, forbearance, forbearing,
   forbearingness, fortitude, frugality, gentleness, golden mean,
   happy medium, hindrance, impartiality, imperturbability,
   independence, indulgence, inhibition, injunction, interdict,
   judiciousness, juste-milieu, legal restraint, lenience, leniency,
   lenity, level head, level-headedness, levelheadedness,
   long-sufferance, long-suffering, longanimity, meden agan, mettle,
   middle way, mildness, moderateness, moderation, moderationism,
   monopoly, neutrality, nonviolence, nothing in excess, obduracy,
   pacifism, patience, patience of Job, patientness, perseverance,
   persistence, placidity, poise, possession, presence of mind,
   prohibition, protection, protectionism, protective tariff,
   prudence, rationing, rein, renouncement, renunciation, repose,
   reserve, resoluteness, resolve, restraint, restraint of trade,
   retardation, retrenchment, self-abnegation, self-assurance,
   self-command, self-confidence, self-conquest, self-denial,
   self-discipline, self-government, self-mastery, self-possession,
   self-restraint, serenity, slowing down, soberness, sobriety,
   sophrosyne, stability, steadfastness, steadiness, stoicism,
   sufferance, sweet reasonableness, tariff wall, temperance,
   temperateness, thought control, tolerance, toleration,
   tranquillity, unexcessiveness, unextravagance, unextremeness,
   via media, waiting game, waiting it out, well-regulated mind, will,
   willpower