Noun
(informal, music) A jazz performer, especially one from the 1940s and 1950s.
(informal, dated, now often humorous) A person associated with the jazz subculture of the 1940s and 1950s.
Synonym: hepster
(informal, dated) A sophisticated person, one who is stylish.
Source: en.wiktionary.orgHepcat gets the invitation — and it makes the younger — but more neurotic — Smartmom question what she’s accomplished in life. Source: Internet