Pretentiously affected (4)
I believe the answer is:
arty
'pretentiously affected' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for arty that I've seen before include "Keen on paintings etc" , "Pretentiously artistic" , "Affectedly highbrow" , "Affectedly cultural" , "Culturally creative" .)