Avenge and revenge are closely related, but they do not work the same way in a sentence.
Avenge is usually a verb. It means to punish or take action because of a wrong done to someone or something. You usually avenge a person, a death, or a harm. Example: He vowed to avenge his brother.
Revenge is usually a noun. It means retaliation or payback for a wrong, often driven by personal anger or hurt. Example: She wanted revenge after the betrayal.
A quick way to remember the difference is this:
- You avenge someone or something.
- You seek or want revenge.
People sometimes use revenge as a verb in informal speech, as in I will revenge this insult, but that is much less common in modern standard English. In most cases, avenge is the better verb choice.
If you are talking about the action, use avenge. If you are naming the feeling or the payback itself, use revenge.