The Collaborative International Dictionary of English v.0.48:

Disharmony \Dis*har"mo*ny\, n.
   Want of harmony; discord; incongruity. [R.]
   [1913 Webster]

         A disharmony in the different impulses that constitute
         it [our nature].                         --Coleridge.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disharmony
    n 1: a lack of harmony [syn: disharmony, inharmoniousness]

Moby Thesaurus II by Grady Ward, 1.0:

103 Moby Thesaurus words for "disharmony":
   Discordia, Eris, antagonism, argumentation, atonalism, atonality,
   cacophony, clash, clashing, clinker, conflict, contention,
   contradiction, controversy, derangement, difference, disaccord,
   disaccordance, disaffinity, disagreement, disarrangement, disarray,
   disarticulation, discomfiture, discomposure, disconcertedness,
   discord, discordance, discordancy, discrepancy, dishevelment,
   disintegration, disjunction, disorder, disorderliness,
   disorganization, disparity, disproportion, disruption, dissension,
   dissent, dissidence, dissonance, dissonancy, dissonant chord,
   disturbance, disunion, disunity, divergence, diversity, enmity,
   entropy, faction, flatness, friction, haphazardness, inaccordance,
   incoherence, incompatibility, incompatibleness, indiscriminateness,
   inequality, inharmonious harmony, inharmoniousness, inharmony,
   irregularity, jangle, jar, jarring, mischief,
   most admired disorder, negation, noncooperation, nonsymmetry,
   nonuniformity, off note, open conflict, opposition, oppugnancy,
   perturbation, promiscuity, promiscuousness, randomness, repugnance,
   rub, sharpness, sour note, sourness, strained relations, stridor,
   strife, tension, tunelessness, turbulence, unharmoniousness,
   unmusicality, unpleasantness, unsymmetry, untunefulness,
   ununiformity, upset, variance, wolf