Lie
To lie is to make statements that are untrue, where the falsity of such statements is known by the speaker. Lying is against the moral standards of many people and is specifically prohibited as a sin in many religions.
A liar is a person who is known to have a tendency to tell lies. People's tolerance for liars is generally very small, and it is often only necessary to be caught lying once to be labelled as a liar and not trusted ever again.
Lying is the subject of many paradoxes, the most famous one being the sentence "This is a lie" which is logically neither true nor false.
See also: The Boy who cried Wolf!
Lie or lie down also means to rest horizontally on a surface, such as a bed.