1. A pathological use of obscene or filthy language.
2. The excessive and uncontrollable use of foul or obscene language, including words related to feces (bowel waste).
3. A compulsive, stereotyped use of obscene language, particularly of words relating to feces; seen in some cases of schizophrenia (mental disorder) and Gilles de la Tourette syndrome.

Coprolalia is a typical symptom of Tourette syndrome, a condition that has its onset in childhood and is characterized by compulsive arm movements, facial tics, grunting, groaning and shouting.

Aside from coprolalia, there is often echolalia, the involuntary parrot-like repetition (echoing) of a word or sentence just spoken by another person. People with Tourette syndrome do not usually curse out of anger or displeasure but out of uncontrollable compulsion. They cannot help themselves. The disease is also called Gilles de la Tourette syndrome.