unpleasantness

from WordNet (r) 3.0 (2006)

unpleasantness
    n 1: the feeling caused by disagreeable stimuli; one pole of a
         continuum of states of feeling [ant: {pleasantness}]
    2: the quality of giving displeasure; "the recent unpleasantness
       of the weather" [ant: {pleasantness}, {sweetness}]

from The Collaborative International Dictionary of English v.0.48

Unpleasant \Un*pleas"ant\, a.
   Not pleasant; not amiable or agreeable; displeasing;
   offensive. -- {Un*pleas"ant*ly}, adv. -- {Un*pleas"ant*ness},
   n.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

46 Moby Thesaurus words for "unpleasantness":
      Discordia, Eris, badness, clash, clashing, conflict, contention,
      damnability, disaccord, disaffinity, discord, discordance,
      discordancy, disharmony, enmity, evilness, friction, improperness,
      inaccuracy, inauspiciousness, incompatibility, incompatibleness,
      inexpedience, inferiority, inharmoniousness, inharmony, invalidity,
      jangle, jar, malevolence, mischief, moral badness, noncooperation,
      open conflict, peccancy, reprehensibility, rub, strained relations,
      tension, unfavorableness, unharmoniousness, unhealthiness,
      unkindness, unskillfulness, viciousness, wickedness