Excellent American man who is well dressed (5)
I believe the answer is:
dandy
I believe this is a double definition.
'excellent american' is the first definition.
(US term meaning excellent)
'man who is well dressed' is the second definition.
(old-fashioned term for a fashionable man)
(Other definitions for dandy that I've seen before include "Fashionable fellow" , "Old comic" , "Playboy" , "See 6" , "Marathon running strips" .)