Social gaffe (4,3)
I believe the answer is:
faux pas
'social gaffe' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for faux pas that I've seen before include "Socially tactless act" , "Socially awkward act" , "Social gaffe" , "Bloomer" , "Social indiscretion" .)