pledge

(plĕj)

1. 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.
2. a. Something given or held as security to guarantee payment of a debt or fulfillment of an obligation.
   b. The condition of something thus given or held: put an article in pledge.
3. Law
   a. Delivery of goods or personal property as security for a debt or obligation: a loan requiring a pledge of property.
   b. The contract by which such delivery is made.
4. A token or sign: “fair pledges of a fruitful tree” (Robert Herrick).
5. 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.
6. The act of drinking in honor of someone; a toast.
7. A vow to abstain from alcoholic liquor: ex-drinkers who have taken the pledge.

1. To offer or guarantee by a solemn binding promise: pledge loyalty to a nation. See Synonyms at devote, promise.
2. To bind or secure by or as if by a pledge: pledged themselves to the cause.
3. To deposit as security; pawn.
4. a. To promise to join (a fraternity or similar organization).
   b. To accept as a prospective member of such an organization.
5. To drink a toast to.

1. To make a solemn binding promise; swear.
2. To drink a toast.