VOW

noun

1. A solemn promise to perform some act, or behave in a specified manner, especially a promise to live and act in accordance with the rules of a religious order.
2. A declaration or assertion.
3. A votive offering.

verb

1. To make a vow; to promise.
2. To make a vow regarding (something).
3. To declare publicly that one has made a vow, usually to show one's determination or to announce an act of retaliation.