pseudologue
/ˈs(j)uːdə(ʊ)lɒɡ/noun
A compulsive liar; a person suffering from pseudologia fantastica.
Origin
1940s; earliest use found in Psychiatric Quarterly. From pseudo- + -logue, largely after pseudologia or its etymon scientific Latin pseudologia. Compare Hellenistic Greek ψευδολόγος liar.