revenge

verb
Verb forms:

 
Word Origin:
late Middle English: from Old French revencher, from late Latin revindicare, from re- (expressing intensive force) + vindicare ‘claim, avenge’.  
Grammar Point:
avenge / revenge
Avenge is a verb; revenge is (usually) a noun.
People avenge something or avenge themselves on somebody: ▪ She vowed to avenge her brother’s death. ◊ ▪ He later avenged himself on his wife’s killers. You take revenge on a person.

In more formal or literary English, revenge can also be a verb. People revenge themselves on somebody or are revenged on them (with the same meaning): ▪ He was later revenged on his wife’s killers. You cannot revenge something: She vowed to revenge her brother’s death.