Detain during wartime (6)
I believe the answer is:
intern
'detain during wartime' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for intern that I've seen before include "Student" , "Medical graduate trainee" , "Novice gaining experience" , "Work experience trainee" , "Confine - physician in US hospital" .)