Damage the reputation of (3)
I believe the answer is:
tar
'damage the reputation of' 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 "Liquid from wood, coal" , "Viscous mixture - sailor" , "Viscous liquid; sailor" , "Black substance, used on roads" , "Tobacco residue; sailor" .)