A person who intentionally deceives others; often carries a strong negative moral judgment. More formal and literary than 詐欺師 (swindler/con artist).
He was a skilled deceiver, and no one could see through his lies.
The politician was denounced as a fraud.
嘘つき is a casual, everyday word for a liar, often used for children or in informal situations. 欺瞞者 is much more serious and formal, implying systematic deception.
Compound of 欺瞞 (giman, 'deception') and 者 (sha, 'person'). The word is a straightforward Sino-Japanese formation.