Procedure for rejecting an antique settee left uncovered outside (9)
I believe the answer is:
etiquette
'procedure' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I can't see?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for etiquette that I've seen before include "Code of polite behaviour" , "Decorum, ceremony" , "Code of conduct" , "Rules observed in polite society" , "Rules of correct behaviour in society" .)