vice

A vice is a moral failing or a bad habit. Lying and cheating are both forms of vice.

In the United States, municipal police departments often have a bureau dedicated to vice, manned by vice cops, whose job it is to fight crime related to alcohol, drugs, and gambling. But anything can be a vice, as long as there's someone out there who views it as bad behavior or a moral weakness. You might say, casually, "Chocolate ice cream is my vice. I eat it every day."