Shine by rubbing (6)
I believe the answer is:
polish
'shine by rubbing' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for polish that I've seen before include "make things shiny" , "Language (linked to spitting?)" , "Shine with cloth,buff" , "Make smooth and glossy" , "Gloss - refinement" .)