1) Adjective for a cool cat 2) American slang for in style 3) Au courant 4) Au courant, once 5) Cadence call 6) Cadence count 7) Cadence shout 8) Cadence word 9) Clued in, once 10) Cool 11) Cool and with it 12) Cool in the 50s 13) Cool old-school 14) Cool, 1940s-style 15) Cool, daddy-o 16) Cool, decades ago 1) Aware 2) Hip 3) Informed 4) Onto 
• (n.) See Hip, the fruit of the dog-rose.
<virology> A high egg passage virus is a weakened virus which is passed on through eggs. ... (09 Oct 1997) ... 
High Explosive Plastic
Hep noun See Hip , the fruit of the dog-rose. 
Hep is American slang for in style. Knowledgeable.
high-explosive plastic
[adj] - (informal) informed about the latest trends
High Energy Physics
hip adjective informed about the latest trends