Twice mother holds the hat for a revered sage (7)
I believe the answer is:
mahatma
'a revered sage' is the definition.
(I've seen this in another clue)
'twice mother holds the hat' is the wordplay.
'twice' shows that letters should be duplicated.
'mother' becomes 'ma' (ma can mean mother).
'holds' means one lot of letters goes inside another.
'ma' duplicated is 'mama'.
'mama' enclosing 'hat' is 'MAHATMA'.
'for' acts as a link.
(Other definitions for mahatma that I've seen before include "(Indian) holy person or sage" , "Wise man" , "Hindu leader" , "Sage (as e.g. Gandhi)" , "In India, a title of respect as for Gandhi" .)