The Collaborative International Dictionary of English v.0.48:

hepcat \hep"cat`\ (h[e^]p"k[a^]t`), n.
   1. One who performs jazz music. [slang]
      [PJC]

   2. A person who is hep or hip; same as hipster; -- an older
      term becoming dated and less used. [slang]
      [PJC]