Black eye make-up (4)
I believe the answer is:
kohl
'black eye make-up' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for kohl that I've seen before include "'Cosmetic preparation, to outline eyes in black (4)'" , "Black powder for eyes" , "Black powder used as eye make-up" , "Former German Chancellor" , "Helmut --, German statesman" .)