Liars and delusionals

[Darkstar]

liar  

noun
a person who tells lies.

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delusional

adjective
1.
having false or unrealistic beliefs or opinions: Senators who think they will get agreement on a comprehensive tax bill are delusional.
2.
Psychiatry. maintaining fixed false beliefs even when confronted with facts, usually as a result of mental illness: He was so delusional and paranoid that he thought everybody was conspiring against him.

For the sake of clarity:

lie  

noun
1. a false statement made with deliberate intent to deceive; an intentional untruth; a falsehood. Synonyms: prevarication, falsification. Antonyms: truth.
2. something intended or serving to convey a false impression; imposture: His flashy car was a lie that deceived no one.
3. an inaccurate or false statement; a falsehood.
4. the charge or accusation of telling a lie: He flung the lie back at his accusers.
verb (used without object)
5. to speak falsely or utter untruth knowingly, as with intent to deceive. Synonyms: prevaricate, fib.
6. to express what is false; convey a false impression.

I have never seen a definition of lie that does not include deliberate deception except the above, but it is not the primary definition, and generally a liar is someone who purposely deceives. Someone who is delusional actually believes the falsehoods they spread, and so by most definitions wouldn't be considered a liar.