Raab's department beginning to pester Rees-Mogg, perhaps (3)
I believe the answer is:
fop
'rees-mogg perhaps' is the definition.
I can't judge whether this definition defines the answer.
'raab's department beginning to pester' is the wordplay.
'raab's department' becomes 'fo' (I can't justify this - if you can you should believe this answer much more).
'beginning to' indicates taking the first letters.
The first letter of 'pester' is 'p'.
'fo'+'p'='FOP'
Can you help me to learn more?
(Other definitions for fop that I've seen before include "exquisite" , "fashionable type" , "A dandy like Beau Brummel" , "Affected dandy" , "Gallant" .)