Pledge
Part of speech: verb
Definition: To make a solemn promise (to do something). To deposit something as a security; to pawn.
Part of speech: noun
Definition: A solemn promise to do something. A person who has taken a pledge of allegiance to a college fraternity, but not yet formally approved. A security to guarantee payment of a debt. A drinking toast. (the pledge): A promise to abstain from drinking alcohol.
Oath
Part of speech: verb
Definition: (archaic) To pledge.Shouting out. (as in 'oathing obsenities')
Part of speech: noun
Definition: A solemn pledge or promise to a god, king or another person, to attest to the truth of a statement or contractthe affirmed statement or promise accepted as equivalent to an oathA light or insulting use of a solemn pledge or promise to a god, king or another person, to attest to the truth of a statement or contract the name of a deity in a profanity, as in swearing oathsa curseAn affirmation of the truth of a statement.