From The Collaborative International Dictionary of English v.0.48 :
Unmatchable \Unmatchable\
See matchable.
From WordNet (r) 3.0 (2006) :
unmatchable
adj 1: 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,
unrivaled, unrivalled]