1. Most aware of or knowledgeable about current trends, fashions, or popular culture; most hip or cool.
Usage: slang; informal; dated (primarily mid-20th century)

Examples

• He considered himself the heppest cat in town with his new suit and slicked-back hair.
• The heppest jazz clubs were always packed on Friday nights.
• She was the heppest dresser in her high school class.
• The heppest musicians of the 1950s influenced generations to come.
• Back then, knowing all the latest slang made you the heppest person around.