Driveway sealant (3)
I believe the answer is:
tar
'driveway sealant' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tar that I've seen before include "Sticky substance used in road construction" , "Sailor (colloq.)" , "Informal sailor or road surfacing material" , "Sticky substance - seaman" , "Sticky cigarette residue" .)