Snappy in quite stylish fashion (5)
I believe the answer is:
testy
'snappy' is the definition.
(I've seen this before)
'in quite stylish fashion' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TESTY' can be found hidden inside 'quite stylish fashion'.
(Other definitions for testy that I've seen before include "Bad-tempered" , "Quick to anger" , "Easily annoyed" , "bad temper" , "Grumpy" .)