Words are supposed to be used to communicate; but too often they are used to deceive or at least to distort the truth. A recent TV survey showed that "the average person lies seven times per day."
A person who lies needs an infallible memory, a vivid imagination and lots of ingenuity. Otherwise he will become inextricably entangled in the web of his own lies. As Sir Walter Scott said, "What a tangled web we weave/when first we practice to deceive."
The worst thing that can happen to a liar is to lose the trust of others. He can tell the truth, and because it is known that he is a liar, no one will believe him.
This was graphically depicted in recent movies about a little girl who had earned a reputation for prevaricating. She accused her father of sexual abuse, but everyone believed it was just another of her fanciful tales. No one believed her — until her father was caught in the act of molesting another child. Even a psychopathic liar sometimes tells the truth.