Be denigrating rugby player, part European (8)
I believe the answer is:
backbite
'be denigrating' is the definition.
I can't tell whether this definition defines the answer.
'rugby player part european' is the wordplay.
'rugby player' becomes 'back' (type of rugby player).
'part' becomes 'bit' (both mean a piece of something).
'european' becomes 'E' (abbreviation e.g. EU).
'back'+'bit'+'e'='BACKBITE'
Can you help me to learn more?
(Other definitions for backbite that I've seen before include "in the same place when translated?" , "Say spiteful things about an absentee" , "Talk spitefully about absent person" , "Say mean things" , "Speak unkindly of (someone) in their absence" .)