One of several terms applied to the behavior of habitual or compulsive lying. The stories are not entirely improbable and often have some element of truth. They are not a manifestation of delusions or some wider form of psychosis: upon confrontation, the person can acknowledge them to be untrue, even if unwillingly.
The telling of elaborate and fictitious stories as if they were true. Often some facts are woven into the tissue of lies. While not necessarily a symptom of illness, it is sometimes a feature of chronic mental illness and of personality disorders, particularly psychopathy.
Pathological lying, usually for psychological reasons rather than for personal gain. The condition is considered to be a type of factitious disorder.