Chessman not initially black? (5)
I believe the answer is:
night
'black?' is the definition.
(thesaurus)
'chessman not initially' is the wordplay.
'chessman' becomes 'knight' (knight is a kind of chessman).
'not initially' means to remove the first letter.
'knight' with its initial letter taken off is 'NIGHT'.
(Other definitions for night that I've seen before include "The dark time" , "Time for bed" , "death" , "Period of darkness" , "Darkness; see you in the morning" .)