A beating by father hurt (7)
I believe the answer is:
pasting
'a beating' is the definition.
The definition and answer are not the same part of speech.
'by father hurt' is the wordplay.
'by' means one lot of letters go next to another.
'father' becomes 'pa' (pa is a kind of father).
'hurt' becomes 'sting' (sting is a kind of hurt**).
'pa' next to 'sting' is 'PASTING'.
Can you help me to learn more?
(Other definitions for pasting that I've seen before include "often followed by hanging" , "Sticking" , "Heavy defeat" .)