A solemn binding promise to do, give, or refrain from doing something: signed a pledge never to reveal the secret; a pledge of money to a charity. Something given or held as security to guarantee payment of a debt or fulfillment of an obligation. The condition of something thus given or held: put an article in pledge. Law Delivery of goods or personal property as security for a debt or obligation: a loan requiring a pledge of property. Law The contract by which such delivery is made. A token or sign: "fair pledges of a fruitful tree\u201d ( Robert Herrick). A person who has been accepted for membership in a fraternity or similar organization and has promised to join but has not yet been initiated. The act of drinking in honor of someone; a toast. A vow to abstain from alcoholic liquor: ex-drinkers who have taken the pledge. To offer or guarantee by a solemn binding promise: pledge loyalty to a nation. See Synonyms at devote, promise. To bind or secure by or as if by a pledge: pledged themselves to the cause. To deposit as security; pawn. To promise to join (a fraternity or similar organization). To accept as a prospective member of such an organization. To drink a toast to. To make a solemn binding promise; swear. To drink a toast.