We don't have synonyms for halfbreed yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are half-breed, half breed and half-bred.
(n) :
Alternative form of half-breed. [(dated, derogatory, offensive, ethnic slur) A person of mixed racial parentage or ancestry, especially one of mixed white and American Indian parentage (metis, métis, Metis, Métis; mestizo).]
(n) :
Alternative form of half-breed. [(dated, derogatory, offensive, ethnic slur) A person of mixed racial parentage or ancestry, especially one of mixed white and American Indian parentage (metis, métis, Metis, Métis; mestizo).]