The years when one finished in being sent astray? (5)
I believe the answer is:
teens
'the years' is the definition.
(I have seen 'Adolescent years' mean 'teens' so perhaps 'years' could also mean 'teens')
'when one finished in being sent astray?' is the wordplay.
I cannot quite see how this works, but
'when' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
'being' could be 'ens' (I've seen this in other clues) and 'ens' is found within the answer.
A single letter 't' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for teens that I've seen before include "seven-year period" , "The years 13 to 19" , "Between 12 and 20" , "Adolescent years" , "children" .)