The Collaborative International Dictionary of English v.0.48:

Unexpected \Unexpected\
   See expected.

The Collaborative International Dictionary of English v.0.48:

Unexpected \Un`ex*pect"ed\, a.
   Not expected; coming without warning; sudden. --
   Un`ex*pect"ed*ly, adv. -- Un`ex*pect"ed*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unexpected
    adj 1: not expected or anticipated; "unexpected guests";
           "unexpected news" [ant: expected]

Moby Thesaurus II by Grady Ward, 1.0:

80 Moby Thesaurus words for "unexpected":
   abrupt, accidental, adventitious, aleatory, antic, breakaway,
   casual, causeless, chance, chancy, contingent, destinal, dicey,
   electrifying, extraordinary, fanciful, fantastic, fatal, fatidic,
   fluky, fortuitous, hasty, headlong, iffy, impetuous, impossible,
   improbable, impulsive, incidental, incomprehensible, inconceivable,
   incredible, indeterminate, more than expected, nerve-shattering,
   offbeat, out-of-the-way, past expectation, precipitant,
   precipitate, precipitous, quick, rare, recherche, risky, shocking,
   speedy, startling, sudden, sui generis, surprising, swift,
   unaccountable, unannounced, unanticipated, unbelievable, uncaused,
   uncommon, uncustomary, undetermined, undivined, undreamed-of,
   unfamiliar, unforeseeable, unforeseen, unguessed, unheard-of,
   unheralded, unhoped for, unimaginable, unique, unlooked-for,
   unordinary, unpredictable, unpredicted, unprepared for,
   unthought-of, unusual, unwonted, without warning