He's too clever to want sour grapes (3)
I believe the answer is:
fox
This clue might be a double definition.
'he's too clever' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'sour grapes' is the second definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'to want' is the link.
Can you help me to learn more?
(Other definitions for fox that I've seen before include "Vulpine creature" , "Trick" , "Baffle; mammal" , "Animal; to cheat" , "Puzzle" .)