Carole is odd revealer of truth (6)
I believe the answer is:
oracle
'revealer of truth' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'carole is odd' is the wordplay.
'is odd' is an anagram indicator.
'carole' is an anagram of 'ORACLE'.
Can you help me to learn more?
(Other definitions for oracle that I've seen before include "Person of great wisdom, as in Delphi of old" , "Prophetic priest/priestess" , "Medium for prophecy" , "Seer" , "Where advice or prophecy was sought from the gods in ancient Greece" .)