At Troon, of course, the tee is one (for starting) (7)
I believe the answer is:
capital
'starting' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I don't see?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for capital that I've seen before include "Big money?" , "Major city - investment - excellent" , "Cardinal; splendid; assets" , "savings" , "Means" .)