Details of his peculiarities (4)
I believe the answer is:
spec
'details' 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?
'of his peculiarities' is the wordplay.
'of' indicates the answer is hidden within the clue.
'SPEC' is hidden in the letters of 'his peculiarities'.
Can you help me to learn more?
(Other definitions for spec that I've seen before include "Detailed design (colloq.)" , "Instructions" , "estimation?" , "Estimate" , "on which chance is taken" .)