Like those bygone days in Colditz (3)
I believe the answer is:
old
'like those bygone days' is the definition.
I can't tell whether this definition defines the answer.
'in colditz' is the wordplay.
'in' says the answer is hidden in the clue.
'OLD' is hidden in the letters of 'colditz'.
Can you help me to learn more?
(Other definitions for old that I've seen before include "Advanced in years" , "Long in the tooth" , "Stale" , "out of the ark" , "Former, previous" .)