Exclusive, upmarket (4)
I believe the answer is:
posh
I believe this clue is a double definition.
'exclusive' is the first definition.
(thesaurus)
'upmarket' is the second definition.
(I've seen this in another clue)
(Other definitions for posh that I've seen before include "Stylishly luxurious" , "'Upper class, accent perhaps (4)'" , "This 13 [SPICE]" , "Upmarket" , "Shop around like upper class" .)