Rough, harsh (6)
I believe the answer is:
coarse
I believe this clue is a double definition.
'rough' is the first definition.
(similar in meaning)
'harsh' is the second definition.
(I know that harsh can be written as coarse)
(Other definitions for coarse that I've seen before include "Rough in texture or crude in manner" , "Rough or crude, lacking refinement" , "Boorish" , "Vulgar - unrefined" , "gross" .)