Source : Webster's Revised Unabridged Dictionary (1913)

Unrivaled \Un*ri"valed\, a.
   Having no rival; without a competitor; peerless. [Spelt also
   {unrivalled}.] --Pope.

Source : WordNet®

unrivaled
     adj : eminent beyond or above comparison; "matchless beauty"; "the
           team's nonpareil center fielder"; "she's one girl in a
           million"; "the one and only Muhammad Ali"; "a peerless
           scholar"; "infamy unmatched in the Western world";
           "wrote with unmatchable clarity"; "unrivaled mastery of
           her art" [syn: {matchless}, {nonpareil}, {one(a)}, {one
           and only(a)}, {peerless}, {unmatched}, {unmatchable}, {unrivalled}]