The Collaborative International Dictionary of English v.0.48:

Tantalize \Tan"ta*lize\, v. t. [imp. & p. p. Tantalized; p.
   pr. & vb. n. Tantalizing.] [From Tantalus: cf. F.
   tantaliser.]
   To tease or torment by presenting some good to the view and
   exciting desire, but continually frustrating the expectations
   by keeping that good out of reach; to tease; to torment.
   [1913 Webster]

         Thy vain desires, at strife
         Within themselves, have tantalized thy life. --Dryden.
   [1913 Webster]

   Syn: To tease; vex; irritate; provoke.

   Usage: Tantalize, Disappoint. To disappoint is literally
          to do away with what was (or was taken to be)
          appointed; hence the peculiar pain from hopes thus
          dashed to the ground. To tantalize, a much stronger
          term, describes a most distressing form of
          disappointment, as in the case of Tantalus, the
          Phrygian king. To tantalize is to visit with the
          bitterest disappointment -- to torment by exciting
          hopes or expectations which can never be realized.
          [1913 Webster]

WordNet (r) 3.0 (2006):

tantalizing
    adj 1: arousing desire or expectation for something unattainable
           or mockingly out of reach; "a tantalizing taste of
           success" [syn: tantalizing, tantalising]
    2: very pleasantly inviting; "a tantalizing aroma"; "a tempting
       repast" [syn: tantalizing, tantalising, tempting]