Die before undertaking parole at camp (8)
I believe the answer is:
password
'parole at camp' is the definition.
(military term for a password)
'die before undertaking' is the wordplay.
'die' becomes 'pass'.
'before' means one lot of letters go next to another.
'undertaking' becomes 'word' (as in a promise, giving one's word).
'pass'+'word'='PASSWORD'
(Other definitions for password that I've seen before include "It's something to admit" , "key" , "Eg, open sesame" , "ID (to access computer)" , "keep this secret?" .)