1275-1325;Middle Englishplege < Anglo-French < early Medieval Latinplevium,plebium, derivative of plebīre to pledge < Germanic; compare Old Englishplēon to risk, Germanpflegen to look after. See plight2
interpledge, verb (used with object), interpledged, interpledging.
prepledge, verb (used with object), prepledged, prepledging; noun
mid-14c., "surety, bail," from O.Fr. plege (Fr. pleige) "hostage, security, bail," probably from Frank. *plegan "to guarantee," from a W.Gmc. root meaning "have responsibility for" (cf. O.Saxon plegan "vouch for," O.H.G. pflegan "to care for, be accustomed to," O.E. pleon "to risk, expose to danger"). Meaning "allegiance vow attested by drinking with another" is from 1630s. Sense of "solemn promise" first recorded 1814, though this meaning is from c.1400 in the verb. Weekley notes the "curious contradiction" in pledge "to toast with a drink" (1540s) and pledge "the vow to abstain from drinking" (1833). Noun meaning "student who has agreed to join a fraternity or sorority" dates from 1901.