mythomane

[ mith-uh-meyn ]
/ ˈmɪθ əˌmeɪn /

noun

a person with a strong or irresistible propensity for fantasizing, lying, or exaggerating.

adjective

of, relating to, or characteristic of a mythomane.

Origin of mythomane

First recorded in 1950–55; perhaps back formation from mythomania
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019