Street-smart (3)
I believe the answer is:
hip
'street-smart' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hip that I've seen before include "Fashionable" , "In modern slang, cool and sophisticated" , "Slangily stylish like rose fruit" , "In slang, trendy or stylish like body joint" , "flask here?" .)