Mammoth trapper (3)
I believe the answer is:
tar
'mammoth trapper' 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 "Tobacco residue; sailor" , "Sailor (colloq.)" , "Dark liquid used on roads" , "It paves the way" , "Hearty" .)