Sage Derby perhaps feeding old women? (7)
I believe the answer is:
mahatma
'sage' is the definition.
(term for a wise Hindu leader)
'derby perhaps feeding old women?' is the wordplay.
'derby perhaps' becomes 'hat' (derby is a type of hat).
'feeding' means one lot of letters goes inside another.
'old women?' becomes 'mama' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'hat' placed into 'mama' is 'MAHATMA'.
(Other definitions for mahatma that I've seen before include "Brahman sage" , "(Indian) holy person or sage" , "Wise man" , "Gandhi's title" , "Great Soul, as Gandhi was called" .)