Hat, for a Texan oil magnate perhaps (7)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
stetson
(Other definitions for stetson that I've seen before include "Man's hat with wide brim and high crown" , "St Neots (anag.)" , "Capital investment" , "Cowboy wear" , "Large hat" .)