Definitions of pledge:

• noun:   a drink in honor of or to the health of a person or event
• noun:   someone accepted for membership but not yet fully admitted to the group
• noun:   a deposit of personal property as security for a debt

  Example: "His saxophone was in pledge"

• noun:   a binding commitment to do or give or refrain from something

  Example: "Signed a pledge never to reveal the secret"

• verb:   pay (an amount of money) as a contribution to a charity or service, especially at regular intervals

  Example: "I pledged $10 a month to my favorite radio station"

• verb:   promise solemnly and formally

  Example: "I pledge that will honor my wife"

• verb:   bind or secure by a pledge

  Example: "I was pledged to silence"

• verb:   give as a guarantee

  Example: "I pledge my honor"

• verb:   propose a toast to