The Collaborative International Dictionary of English v.0.48:

Disaccord \Dis`ac*cord"\, v. i. [Cf. F. d['e]saccorder to cause
   discord.]
   To refuse to assent. [Obs.] --Spenser.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Disaccord \Dis`ac*cord"\, n.
   Disagreement. --Pop. Sci. Monthly.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disaccord
    v 1: be different from one another [syn: disagree,
         disaccord, discord] [ant: agree, check,
         correspond, fit, gibe, jibe, match, tally]

Moby Thesaurus II by Grady Ward, 1.0:

156 Moby Thesaurus words for "disaccord":
   agree to disagree, agreement to disagree, alienation, antagonism,
   antipathy, apostasy, argumentation, bad blood,
   be at cross-purposes, be at variance, be distinct,
   be distinguished, break, break off, clash, clash with, clashing,
   collide, collision, competition, conflict, conflict with,
   contradict, contradiction, contrariety, contrariness, contrast,
   contrast with, controversy, counter, counter-culture,
   cross-purposes, depart from, departure, deviate from, deviation,
   differ, differ in opinion, difference, disaccord with,
   disaccordance, disagree, disagree with, disagreement,
   disapprobation, disapproval, disconformity, discongruity, discord,
   discordance, discordancy, discrepancy, discreteness, disharmony,
   disparity, dissatisfaction, dissension, dissent, dissentience,
   dissidence, dissimilarity, dissonance, distinction, distinctness,
   disunion, disunity, divaricate from, diverge, diverge from,
   divergence, divergency, diversity, divide, dropping out, enmity,
   estrangement, faction, far cry, fractiousness, friction,
   heterogeneity, hold opposite views, hostility, inaccordance,
   incompatibility, incongruity, inconsistency, inconsonance,
   inequality, inharmoniousness, inharmony, inimicalness,
   irreconcilability, jangle, jar, jar with, jarring, jostle,
   minority opinion, mismatch, mismate, misunderstand one another,
   mixture, negate, negation, negativeness, nonagreement, nonassent,
   noncompliance, nonconcurrence, nonconformance, nonconformism,
   nonconformity, nonconsent, noncooperation, nonobservance,
   not accord with, not get along, not square with, object, obstinacy,
   odds, opposition, oppugnancy, originality, otherness, perverseness,
   protest, pull different ways, recalcitrance, recusance, recusancy,
   refractoriness, rejection, repudiation, repugnance, rivalry,
   ruffled feelings, secession, separateness, stand apart,
   stand over against, strained relations, unconformity,
   uncooperativeness, underground, unharmoniousness, unlikeness,
   unorthodoxy, variance, variation, variegation, variety, vary,
   vying, withdrawal