The Collaborative International Dictionary of English v.0.48:

Shakespearean \Shake*spear"e*an\, a.
   Of, pertaining to, or in the style of, Shakespeare or his
   works. [Written also Shakespearian, Shakspearean,
   Shakspearian, Shaksperean, Shaksperian.etc.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Shakespearean
    adj 1: of or relating to William Shakespeare or his works;
           "Shakespearean plays" [syn: Shakespearian,
           Shakespearean]
    n 1: a Shakespearean scholar [syn: Shakespearian,
         Shakespearean]