Early American tycoon (5)
I believe the answer is:
astor
'early american 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 "First female MP" , "Female politician" , "Nancy --, one-time MP" , "Nancy ---, first woman MP" , "See 2" .)