vow

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.

"The old hermit, up in the mountains, took a vow of silence."

A declaration or assertion.

A votive offering.

To make a vow; to promise.

To make a vow regarding (something).

"The wronged woman vowed revenge."

To declare publicly that one has made a vow, usually to show one's determination or to announce an act of retaliation.

"The rebels vowed to continue their fight."