'Unpleasantness' definitions:

Definition of 'unpleasantness'

From: WordNet
noun
The feeling caused by disagreeable stimuli; one pole of a continuum of states of feeling [ant: pleasantness]
noun
The quality of giving displeasure; "the recent unpleasantness of the weather" [ant: pleasantness, sweetness]

Definition of 'Unpleasantness'

From: GCIDE
  • 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]