unpleasantly

from WordNet (r) 3.0 (2006)

unpleasantly
    adv 1: in an unpleasant manner; "he had been unpleasantly
           surprised" [ant: {agreeably}, {enjoyably}, {pleasantly}]

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]