Quick, agile (5)
I believe the answer is:
nifty
I believe this clue is a double definition.
'quick' is the first definition.
(thesaurus)
'agile' is the second definition.
(I've seen this before)
(Other definitions for nifty that I've seen before include "Quick - stylish" , "Smart" , "Stylish; agile (informal)" , "Really good (slang)" , "Particularly effective; stylish" .)