controversial

from WordNet (r) 3.0 (2006)

controversial
    adj 1: marked by or capable of arousing controversy; "the issue
           of the death penalty is highly controversial"; "Rushdie's
           controversial book"; "a controversial decision on
           affirmative action" [ant: {noncontroversial},
           {uncontroversial}]

from The Collaborative International Dictionary of English v.0.48

Controversial \Con`tro*ver"sial\, a. [Cf. LL. controversialis.]
   Relating to, or consisting of, controversy; disputatious;
   polemical; as, controversial divinity.
   [1913 Webster]

         Whole libraries of controversial books.  --Macaulay.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

51 Moby Thesaurus words for "controversial":
      arguable, argumental, argumentative, at issue, belligerent,
      cat-and-dog, cat-and-doggish, combative, confutable, conjectural,
      contentious, contestable, controvertible, debatable, deniable,
      dialectic, disputable, disputatious, doubtable, doubtful, dubious,
      dubitable, eristic, factious, iffy, ill-humored, in dispute,
      in doubt, in dubio, in question, litigious, logomachic, mistakable,
      moot, open to doubt, open to question, pilpulistic, polemic,
      polemical, pro and con, problematic, provocative, quarrelsome,
      questionable, refutable, scrappy, speculative, suppositional,
      suspect, suspicious, unsettled