noun
(also mainpernour)
historical Law A person who stands surety that another (especially a prisoner) will fulfil a legal obligation to appear in court on a specified day.
Origin
Middle English; earliest use found in Statutes of the Realm. From Anglo-Norman mainpernour, meinparnour, mainprenur from mainprendre to act as guarantee, probably after post-classical Latin manucapere.
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