The Collaborative International Dictionary of English v.0.48:
Mongrelize \Mon"grel*ize\, v. t. & i. To cause to be mongrel; to cross breeds, so as to produce mongrels. [1913 Webster]WordNet (r) 3.0 (2006):
mongrelize v 1: cause to become a mongrel; "mongrelized dogs" [syn: mongrelize, mongrelise]