vow

nouns

a solemn pledge (to oneself or to another or to a deity) to do something or to behave in a certain manner
"they took vows of poverty"
vow
is a type of (narrower)
a binding commitment to do or give or refrain from something
"an assurance of help when needed"; "signed a pledge never to reveal the secret"
assurance, pledge

verbs

make a vow; promise
"He vowed never to drink alcohol again"
vow
is derived from
vower
is a type of (narrower)
promise solemnly and formally
"I pledge that I will honor my wife"
pledge, plight
dedicate to a deity by a vow
consecrate, vow