Source : Webster's Revised Unabridged Dictionary (1913)

Lackadaisical \Lack`a*dai"si*cal\, a. [From {Lackadaisy},
   interj.]
   Affectedly pensive; languidly sentimental. --
   {Lack`a*dai"si*cal*ly}, adv.

Source : WordNet®

lackadaisical
     adj 1: lacking spirit or liveliness; "a lackadaisical attempt"; "a
            languid mood"; "a languid wave of the hand"; "a hot
            languorous afternoon" [syn: {dreamy}, {languid}, {languorous}]
     2: idle or indolent especially in a dreamy way; "she was
        annoyingly lackadaisical and impractical";
        "a...lackadaisical, spiritless young man-about-town"-
        P.G.Wodehouse