1. Behavior that is contrary to normally acceptable social norms: Mildred's vice was compulsive on-line gambling which resulted in a financial loss of the mortgage on her home.
2. A minor bad and uncontrollable habit: Steve admitted that eating too much was his vice.
3. Criminal activities that can involve sex or drugs or both of them: Bert was arrested by the police who were dealing with such vices as narcotics.

A reporter was investigating a vice in which prostitutes were parked in campers on some streets of the town to entice or to lure customers to come and to visit them.