The Collaborative International Dictionary of English v.0.48:

Displeasant \Dis*pleas"ant\, a. [OF. desplaisant, F.
   d['e]plaisant. See Displease.]
   Unpleasing; offensive; unpleasant. [Obs.] --Speed. --
   Dis*pleas"ant*ly, adv. [Obs.] --Strype. --
   Dis*pleas"ant*ness, n. [Obs.]
   [1913 Webster]