While it is a common stereotype to define the concept of “pathological liar” as meaning “Republican politician,” let’s take a closer look at what this phrase really means.
Etymology:
One of the current definitions of pathological is “caused by or evidencing a mentally disturbed condition.” Pathological came into English in the 1680s with the meaning of “pertaining to disease.” With regard to etymology, pathological is based on pathologic which comes from the Greek “pathologikos.”
Pathological is an adjective which is derived from the noun “pathology” (“science of diseases”) which came into English in the 1610s from the French “pathologie” which is based on the medical Latin “pathologia” meaning “study of disease.” The Latin “pathologia” comes from the Greek “pathos” meaning “suffering” plus “-logia” meaning “study.” In ancient Greek, “pathologia” meant “the study of passions” while “pathologike” meant “science of diseases.”
While “pathology” originally referred to the study of physical diseases, in 1842 the meaning of the word was extended to include mental diseases as well.
Liar began being used in English in the early thirteenth century. It is based on the Old English “leogere” meaning “false witness” which comes from the Anglian “legan” and the West Saxon “leogan” meaning “be untruthful, lie.” Etymologists feel that the –ar ending was probably introduced in imitation of such forms as “scholar” for “scoler” and “pillar” for “piler.”
Liar is based on the verb “to lie” (meaning “to speak falsely, tell an untruth”) which first appeared in English in the late twelfth century and stemmed from the Proto-Germanic “*leugan” which in turn came from the Proto-Indo-European root “*laugh-” meaning “to tell a lie.”
Note: In etymologies, the * indicates that the Proto-Indo-European or prehistoric word has been reconstructed by historical linguists.
Psychology:
The website WikiHow has this to say about the pathological liar:
“This person may not be completely rooted in reality, believing the lies they tell, often in an effort to remedy low self esteem. Unlike telling a few fibs here and there, or slightly exaggerating the truth once in a while, the pathological liar lies about literally every aspect of his or her life.”
For the pathological liar, the truth is often uncomfortable. Pathological liars often lie as an attempt to avoid getting into trouble—lying is a way of shifting the blame. At the same time, pathological liars may lie to gain attention and to feel important. Pathological liars often do not live in reality.
While it is fairly common to use the terms “compulsive liar” and “pathological liar” interchangeably, there is in fact a significant difference: pathological liars lie only when it will help them in some way, while compulsive liars feel a need to lie regardless of the situation.
Pathological lying is often associated with the false memory syndrome in which the person truly believes that certain false events have actually taken place.