American's ball on right-winger's head (10)
I believe the answer is:
promontory
'head' is the definition.
(both can mean a cliff or headland)
'american's ball on right-winger's' is the wordplay.
'american's ball' becomes 'prom' (US term for a dance or ball).
'right-winger' becomes 'tory' (Tory is an example).
'prom'+'on'+'tory'='PROMONTORY'
(Other definitions for promontory that I've seen before include "Bill" , "Coastal feature" , "Head" , "Point" , "Headland" .)