Rub it in (5)
I believe the answer is:
gloat
'rub it in' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gloat that I've seen before include "Show malicious smugness" , "Look triumphant" , "Smugly look on another's misfortune" , "Exult maliciously" , "Look like the cat who got the cream" .)