American jerk (4)
I believe the answer is:
yank
This clue is a double definition.
'american' is the first definition.
(Yank can informally mean an American)
'jerk' is the second definition.
(I know that jerk can be written as yank)
(Other definitions for yank that I've seen before include "Big jerk!" , "Term for an American" , "Pull with a sudden movement" , "Pull violently - American" , "Sudden hard pull" .)