*mainpernor*

n. [ OF. main hand + pernor, for preneor, a taker, F. preneur, fr. prendre to take. ] (Law) A surety, under the old writ of mainprise, for a prisoner's appearance in court at a day. [ 1913 Webster ]

☞ Mainpernors differ from bail in that a man's bail may imprison or surrender him before the stipulated day of appearance; mainpernors can do neither; they are bound to produce him to answer all charges whatsoever. Blackstone. [ 1913 Webster ]