Dines in style at smart restaurants (4)
I believe the answer is:
eats
'dines' is the definition.
(I've seen this before)
'in style at smart restaurants' is the wordplay.
'in' indicates the answer is hidden within the clue.
'EATS' is hidden within 'style at smart restaurants'.
(Other definitions for eats that I've seen before include "Tuck" , "Takes meals" , "worrying" , "Food (slang)" , "bits of food" .)