Man in the dark, reportedly (6)
I believe the answer is:
knight
'man' is the definition.
(man can mean a piece in chess)
'the dark reportedly' is the wordplay.
'the dark' becomes 'night' (night is a kind of dark).
'reportedly' shows a homophone (sound like).
'night' sounds like 'KNIGHT'.
'in' is the link.
(Other definitions for knight that I've seen before include "Old freelance" , "Heroic champion" , "He was trained in arms and chivalry in olden days" , "Male honoured by the British sovereign" , "'Chessman, the horse's head (6)'" .)