sponsionEtymologyFrom Latin spōnsiō, from spondēre (“to promise solemnly”).sponsion means the act of becoming surety for another. Lexicurio rates it Sui generis — a strength score of 87 out of 100.nounThe act of becoming surety for another.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.