Mongrel

In the year 5,000,000,000, Cassandra O'Brien.Δ17, who claimed herself to be the last "pure" human, branded the rest of the human race, who had all "mingled" by that time, as mongrels. (TV: The End of the World)

In Montgomery in 1955, Mason referred to Ryan Sinclair and Yasmin Khan as mongrels. (TV: Rosa)