NOUN (1)

1. a bad or unsuitable match;


VERB (1)

1. match badly; match two objects or people that do not go together;

The Collaborative International Dictionary of English v.0.48:

Mismatch \Mis*match"\, v. t.
   To match unsuitably.
   [1913 Webster]

WordNet (r) 3.0 (2006):

mismatch
    n 1: a bad or unsuitable match
    v 1: match badly; match two objects or people that do not go
         together