Juvenile's released at jail (6)
I believe the answer is:
immure
'jail' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for immure that I've seen before include "Confine; wall in" , "Imprison, shut in" , "Sketches" , "Imprison within walls" , "Shut oneself away from social contact" .)