Rather so myself, wouldn’t you agree? (8)
I believe the answer is:
somewhat
'rather' is the definition.
(I've seen this before)
'so myself wouldn't you agree?' is the wordplay.
I cannot really see how this works, but
'so' is found in the answer.
'myself' could be 'me' and 'me' is found within the answer.
The remaining letters 'what' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for somewhat that I've seen before include "To some degree, sort of" , "To a moderate extent" , "To a certain degree - a bit" , "To an extent, a little" , "Quite" .)