Young trainee from America, determined (5)
I believe the answer is:
cadet
'young trainee' is the definition.
(eg an army cadet)
'from america determined' is the wordplay.
'from' says the answer is hidden in the clue.
'CADET' is hidden within 'america determined'.
(Other definitions for cadet that I've seen before include "Younger member of family" , "Military trainee officer" , "Tomboy" , "Trainee cop" , "who needs to be properly trained?" .)