In sociology, deviance describes an action or behavior that violates social norms, including a formally enacted rule (e.g., crime),as well as informal violations of social norms (e.g., rejecting folkways and mores). It is the purview of criminologists, psychiatrists, psychologists, and sociologists to study how these norms are created, how they change over time, and how they are enforced.
Norms are rules and expectations by which members of society are conventionally guided. Deviance is an absence of conformity to these norms. Social norms differ from culture to culture. For example, a deviant act can be committed in one society that breaks a social norm there, but may be normal for another society.