Conceal copy in public relations excess (5,4)
I believe the answer is:
paper over
'conceal' is the definition.
(I've seen this before)
'copy in public relations excess' is the wordplay.
'copy' becomes 'ape' (ape can mean to copy or imitate).
'in' indicates putting letters inside.
'public relations excess' becomes 'prover' (I am not sure about this - if you are sure you should believe this answer much more).
'ape' going into 'prover' is 'PAPER OVER'.
Can you help me to learn more?
(Other definitions for paper over that I've seen before include "Conceal" , "Pretend there's no real problem with" , "Try to hide fault" , "Disguise bad news" .)