Good manners; protocol (9)
I believe the answer is:
etiquette
I believe this clue is a double definition.
'good manners' is the first definition.
(thesaurus)
'protocol' is the second definition.
(I've seen this before)
(Other definitions for etiquette that I've seen before include "What's done" , "Rules governing socially acceptable behaviour" , "form" , "Conventional courtesy" , "Convention" .)