A man who belongs to aristocratic or fashionable society; a male inhabitant of the beau monde.
Origin
Mid 19th century; earliest use found in Sydney Morgan (bap. 1783, d. 1859), novelist and socialite. From French mondain, although only attested from 1868 as noun in this sense, and from 1844 as adjective in the corresponding sense ‘concerned with the life of high society’.