An American bowler (5)
I believe the answer is:
derby
'an american bowler' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for derby that I've seen before include "Hat, race and local match" , "Racing classic" , "Annual race at Epsom" , "Cathedral city on the River Derwent" , "Epsom horse-race" .)