breed out (v.)
exhaust through breeding, become degenerate
H5 III.v.29[Dauphin to all] Our madams mock at us, and plainly say / Our mettle is bred out
Tim I.i.254[Apemantus to Alcibiades] The strain of man's bred out / Into baboon and monkey
SHAKESPEARE'S WORDS © 2018 DAVID CRYSTAL & BEN CRYSTAL