Fur-trading tycoon (5)
I believe the answer is:
'fur-trading tycoon' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for astor that I've seen before include "female parliamentarian" , "First female MP" , "Nancy ---, first woman MP" , "See 2" , "Nancy --, one-time MP" .)