Pledge  —n. 1 solemn promise. 2 thing given as security against a debt etc. 3 thing put in pawn. 4 thing given as a token of favour etc., or of something to come. 5 drinking of a person's health, toast. 6 solemn promise to abstain from alcohol (sign the pledge). —v. (-ging) 1 a deposit as security. B pawn. 2 promise solemnly by the pledge of (one's honour, word, etc.). 3 bind by a solemn promise. 4 drink to the health of.  pledge one's troth see *troth. [french plege]