Affectedly snobbish, pretentious (3-2-3)
I believe the answer is:
lah-di-dah
(Other definitions for lah-di-dah that I've seen before include "Affectedly genteel, highfalutin" , "Affectedly posh" , "Pretentious, snobbish (colloq.)" , "Pretentiously refined, affected in speech and manners" , "with a superior attitude?" .)