The Collaborative International Dictionary of English v.0.48:

Shiftless \Shift"less\, a.
   Destitute of expedients, or not using successful expedients;
   characterized by failure, especially by failure to provide
   for one's own support, through negligence or incapacity;
   hence, lazy; improvident; thriftless; as, a shiftless fellow;
   shiftless management. -- Shift"less*ly, adv. --
   Shift"less*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

shiftless
    adj 1: lacking or characterized by lack of ambition or
           initiative; lazy; "a shiftless student"; "studied in a
           shiftless way"

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "shiftless":
   aimless, bone-lazy, cadging, dilatory, do-nothing, doless, dronish,
   drony, easy, ergophobic, faineant, feckless, good-for-nothing,
   grasshopper, happy-go-lucky, heedless, idle, improvident, indolent,
   ineffective, irresponsible, lackadaisical, laggard, lax, lazy,
   negligent, nonaggressive, otiose, parasitic, pococurante,
   procrastinative, remiss, scrounging, slack, slothful, slow,
   sponging, thoughtless, thriftless, unambitious, uncaring,
   uneconomical, unenterprising, uninspired, unmotivated, unproviding,
   unthrifty, work-shy