They maybe drop hints, surprisingly concealing evidence of doubt (5,6)
I believe the answer is:
third person
'evidence of doubt' 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?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for third person that I've seen before include "reason for an eternal triangle" , "stopped by Ancient Mariner?" , "will suggest PC title for Greene novel?" , "Maybe they" , "could be murderer" .)