blackmail Definition

blackmail
verb

1. To extort money, etc illegally from someone by threatening to reveal harmful information about them.
2. To try to influence someone by using unfair pressure or threats.

noun

1. An act of blackmailing someone.

Derivative: blackmailer
noun

Etymology: 16c in historical sense ‘a payment made to robbers for protection': from black adj 6 + obsolete mail payment of money.