Put off being freed indefinitely (5)
I believe the answer is:
defer
'put off' is the definition.
(synonyms)
'freed indefinitely' is the wordplay.
'indefinitely' indicates an anagram (indefinitely can mean vaguely or uncertainly).
'freed' is an anagram of 'DEFER'.
'being' is the link.
(Other definitions for defer that I've seen before include "put on ice" , "Yield to another's wishes" , "Give precedence to" , "Freed (anag.)" , "Hold over, put off" .)