Prison term for what whistle-blower's announced? (4,5)
I believe the answer is:
time limit
'what whistle-blower's announced?' is the definition.
'prison term' is the wordplay.
'prison' becomes 'time' (as in a spell in prison).
'term' becomes 'limit' (I've seen this before).
'time'+'limit'='TIME-LIMIT'
'for' is the link.
(Other definitions for time limit that I've seen before include "within which task must be done" , "Point before which something must be achieved" , "Deadline" , "maximum duration" , "Prescribed term" .)