A person who lies about everything, without any apparent regard for truth or reality, is often referred to as a "pathological liar" or a "compulsive liar." This behavior is characterized by a persistent and habitual pattern of dishonesty, where the individual may lie for various reasons, such as seeking attention, avoiding consequences, or manipulating others for personal gain. Pathological lying is considered a psychological condition and may be associated with underlying issues like a personality disorder or a history of trauma. It's essential to approach such individuals with empathy and understanding while also being cautious about the trustworthiness of their statements.