Awfully rude urge I suppressed, as required by etiquette (2,7)
I believe the answer is:
de rigueur
'required by etiquette' is the definition.
(I've seen this before)
'awfully rude urge i suppressed' is the wordplay.
'awfully' indicates an anagram.
'suppressed' is an insertion indicator (inserted letters are suppressed by others).
'rude'+'urge'='rudeurge'
'rudeurge' is an anagram of 'dergueur'.
'dergueur' placed around 'i' is 'DE RIGUEUR'.
'as' acts as a link.
(Other definitions for de rigueur that I've seen before include "Proper" , "Required by custom or etiquette" , "Obligatory" , "Required by strict etiquette or fashion (French)" , "necessary" .)