Source : Webster's Revised Unabridged Dictionary (1913)

Interesting \In"ter*est*ing\, a.
   Engaging the attention; exciting, or adapted to excite,
   interest, curiosity, or emotion; as, an interesting story;
   interesting news. --Cowper.

Interest \In"ter*est\, v. t. [imp. & p. p. {Interested}; p. pr.
   & vb. n. {Interesting}.] [From interess'd, p. p. of the older
   form interess, fr. F. int['e]resser, L. interesse. See
   {Interest}, n.]
   1. To engage the attention of; to awaken interest in; to
      excite emotion or passion in, in behalf of a person or
      thing; as, the subject did not interest him; to interest
      one in charitable work.

            To love our native country . . . to be interested in
            its concerns is natural to all men.   --Dryden.

            A goddess who used to interest herself in marriages.
                                                  --Addison.

   2. To be concerned with or engaged in; to affect; to concern;
      to excite; -- often used impersonally. [Obs.]

            Or rather, gracious sir, Create me to this glory,
            since my cause Doth interest this fair quarrel.
                                                  --Ford.

   3. To cause or permit to share. [Obs.]

            The mystical communion of all faithful men is such
            as maketh every one to be interested in those
            precious blessings which any one of them receiveth
            at God's hands.                       --Hooker.

   Syn: To concern; excite; attract; entertain; engage; occupy;
        hold.

Source : WordNet®

interesting
     adj : arousing or holding the attention [ant: {uninteresting}]

Source : Free On-Line Dictionary of Computing

interesting
     
        In hacker parlance, this word has strong connotations of
        "annoying", or "difficult", or both.  Hackers relish a
        challenge, and enjoy wringing all the irony possible out of
        the ancient Chinese curse "May you live in interesting times".
     
        [{Jargon File}]