pledge

Concise Oxford English Dictionary © 2008 Oxford University Press:
pledge/pleʤ/

▶noun

• 1 a solemn promise or undertaking.

  ■ a promise of a donation to charity.

  ■ (the pledge) a solemn undertaking to abstain from alcohol.

• 2 Law a thing that is given as security for the fulfilment of a contract or the payment of a debt and is liable to be forfeited in the event of failure.

  ■ a thing given as a token of love, favour, or loyalty.

• 3 archaic the drinking of a person's health; a toast.

▶verb

• 1 solemnly undertake to do or give something.

• 2 Law give as security on a loan.

• 3 archaic drink to the health of.

– derivatives
pledgee noun (Law),
pledger noun,
pledgor noun (Law).

– origin ME (denoting a person acting as surety for another): from OFr. plege, from med. L. plebium, perh. rel. to the Gmc base of plight2.