n. [ L. sponsio, fr. spondere, sponsum, to promise solemnly. ] 1. The act of becoming surety for another. [ 1913 Webster ]

2. (Internat. Law) An act or engagement on behalf of a state, by an agent not specially authorized for the purpose, or by one who exceeds the limits of authority. [ 1913 Webster ]

a. Of or pertaining to a pledge or agreement; responsible. [ R. ] [ 1913 Webster ]

He is righteous even in that representative and sponsional person he put on. Abp. Leighton. [ 1913 Webster ]