Here's your chance to play detective (4)
I believe the answer is:
clue
'play detective' is the 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?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for clue that I've seen before include "Hint towards solution" , "What's this" , "Part of a crossword" , "Aid to puzzlers" , "one of 28 here" .)