A rude GP arranged improvement (7)
I believe the answer is:
upgrade
'improvement' is the definition.
(I know that upgrade is a type of improvement)
'a rude gp arranged' is the wordplay.
'arranged' indicates an anagram (letters rearranged).
'a'+'rude'+'gp'='arudegp'
'arudegp' with letters rearranged gives 'UPGRADE'.
(Other definitions for upgrade that I've seen before include "promotion" , "Improve equipment or promote" , "Raise in status or quality" , "advance" , "Improve, enhance" .)