Webster's 1828 Dictionary
MISMATCHED
pp. Unsuitably matched; ill joined.
American Oxford Thesaurus
mismatched
mismatched adjective mismatched socks | a mismatched couple: ill-assorted, ill-matched, incongruous, unsuited, incompatible, inconsistent, at odds; out of keeping, clashing, dissimilar, unalike, different, at variance, disparate, unrelated, divergent, contrasting. ANTONYMS matching.
Oxford Thesaurus
mismatched
mismatched adjective mismatched kitchen units: ill-assorted, ill-matched, incongruous, unsuited, incompatible, inharmonious, conflicting, inconsistent, opposed, at odds; out of keeping, clashing, discrepant; uneven, dissimilar, unlike, unalike, different, varying, variant, at variance, disparate, unrelated, divergent, deviating, diverse, various, contrasting, distinct. ANTONYMS matching, compatible.