The Collaborative International Dictionary of English v.0.48:

Exhaustive \Ex*haust"ive\, a.
   Serving or tending to exhaust; exhibiting all the facts or
   arguments; as, an exhaustive method. Ex*haust"ive*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

exhaustive
    adj 1: performed comprehensively and completely; "an exhaustive
           study"; "made a thorough search"; "thoroughgoing
           research" [syn: exhaustive, thorough,
           thoroughgoing]

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "exhaustive":
   absolute, aggregate, all, all-embracing, all-encompassing,
   all-inclusive, all-out, all-pervading, born, broad-based, clean,
   clear, complete, comprehensive, congenital, consequential,
   considerable, consummate, deep, deep-dyed, downright,
   dyed-in-the-wool, egregious, encyclopedic, entire, extensive,
   far-reaching, full, full-dress, full-scale, fully realized, grand,
   grave, great, gross, heavy, holistic, inclusive, integral,
   integrated, intense, intensive, irresistible, main, maximal,
   maximum, mighty, omnibus, omnipresent, one, one and indivisible,
   out-and-out, outright, perfect, pervasive, plain, plenary, plumb,
   polished, powerful, pure, radical, regular, serious, sheer,
   straight, strong, sweeping, thorough, thoroughgoing,
   through-and-through, total, ubiquitous, unconditional, universal,
   unmitigated, unqualified, unreserved, unrestricted, utter,
   veritable, whole, wholesale