A sharp rebuke about cakes (4)
I believe the answer is:
snub
'a sharp rebuke' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'about cakes' is the wordplay.
'about' is a reversal indicator.
'cakes' becomes 'buns' (cake is a type of bun).
'buns' back-to-front is 'SNUB'.
Can you help me to learn more?
(Other definitions for snub that I've seen before include "Reject greeting, seek to humiliate" , "put down" , "Reject greeting or approach" , "Rebuff; brush-off" , "Ignore, spurn disdainfully" .)