frankpledge

noun

frank·​pledge ˈfraŋk-ˌplej 

: an Anglo-Saxon system under which each adult male member of a tithing was responsible for the good conduct of the others

also : the member himself or the tithing

Word History

Etymology

Middle English frankeplegge, from Anglo-French francplege (probably translation of Middle English friborg peace pledge), from franc free + plege pledge

First Known Use

15th century, in the meaning defined above