The Collaborative International Dictionary of English v.0.48:

lackadaisical \lack`a*dai"si*cal\ (l[a^]k`[.a]*d[=a]"z[i^]*kal),
   a. [From Lackadaisy, interj.]
   1. Affectedly pensive; languidly sentimental; dreamy.
      [1913 Webster]

   2. Lacking spirit or liveliness; lethargic; listless;
      languid.
      [PJC]

   3. Indolent; lazy; idle, especially in a dreamy manner.
      [PJC] -- Lack`a*dai"si*cal*ly, adv.
      [1913 Webster]

WordNet (r) 3.0 (2006):

lackadaisically
    adv 1: in an idle and lackadaisical manner; "he was hanging
           around the house lackadaisically"