Sticky black substance (3)
I believe the answer is:
tar
'sticky black substance' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tar that I've seen before include "Crewman" , "Sailor - laid on road" , "Sticky cigarette residue" , "Informal sailor or coal distillation" , "Sticky road material or informal sailor" .)