The Collaborative International Dictionary of English v.0.48:

Unconditional \Un`con*di"tion*al\, a.
   Not conditional, limited, or conditioned; made without
   condition; absolute; unreserved; as, an unconditional
   surrender.
   [1913 Webster]

         O, pass not, Lord, an absolute decree,
         Or bind thy sentence unconditional.      --Dryden.
   [1913 Webster] -- Un`con*di"tion*al*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unconditional
    adj 1: not conditional; "unconditional surrender" [syn:
           unconditional, unconditioned] [ant: conditional]
    2: not modified or restricted by reservations; "a categorical
       denial"; "a flat refusal" [syn: categoric, categorical,
       flat, unconditional]
    3: not contingent; not determined or influenced by someone or
       something else

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "unconditional":
   absolute, admitting no exception, all-embracing, all-encompassing,
   all-out, all-pervading, born, broad-based, categorical, clean,
   clear, complete, comprehensive, conclusive, congenital, consummate,
   decided, decisive, deep-dyed, definite, definitive, determinate,
   downright, dyed-in-the-wool, egregious, entire, exhaustive,
   explicit, express, final, fixed, flat, flat-out, full, global,
   illimitable, implicit, inappealable, indisputable, intensive,
   limitless, no strings, omnibus, omnipresent, open, out-and-out,
   outright, peremptory, perfect, pervasive, plain, plenary, plumb,
   positive, pure, radical, regular, round, sheer, straight,
   straight-out, sweeping, thorough, thoroughgoing,
   through-and-through, total, ubiquitous, unbound, unbounded,
   uncircumscribed, unconditioned, unconfined, undoubting,
   unequivocal, unhampered, unhesitating, universal, unlimited,
   unmeasured, unmistakable, unmitigated, unqualified, unquestioning,
   unreserved, unrestricted, unwaivable, utter, veritable, whole,
   wholesale, wide-open, without exception, without reserve,
   without strings



Bouvier's Law Dictionary, Revised 6th Ed (1856):

UNCONDITIONAL. That which is without condition; that which must be performed
without regard to what has happened or may happen.