Extortion (referred to as blackmail) occurs when you use some kind of threat or force which coerces the other individual to provide you with something (money or property). An example could be if a woman threatens to reveal the affair she had with her boss unless he buys her a brand new car.
There are other kinds of extortion. For instance, seeking to influence a public official to act in a manner that benefits you. An example: threatening to publicly accuse a city councilman of bribery unless he votes in support of a new city ordinance.
Penalties for Extortion
The penalties for extortion, a felony, can be up to 4 years in prison and a fine of up to $10,000.