Matters related to criminal behavior in society are studied in the field of sociology on the sub-field of criminology, and a person who studies this is called a criminologist. Psychological assessment of criminals is studied by psychologists.
The term "criminal" is sometimes used as a derogatory accusation of a person when viewing an act attributed to him/her as dangerous or destructive towards other people, or property. However, legally, in almost all jurisdictions, it is acceptable that a person is not guilty until convicted, thus may not be called a "criminal" until proven guilty.
A criminal has a criminal record, detailing the allegations and findings against them.
Most jurisdictions distinguish between civil law and criminal law. Criminal law defines crimes, civil law defines legal obligations and contracts between people.
See also law, crime, punishment, deterrence, prison, war criminal.