At no time content to postpone verdict (5)
I believe the answer is:
never
'at no time' is the definition.
(synonyms)
'content to postpone verdict' is the wordplay.
'content to' indicates a hidden word.
'NEVER' is hidden in the letters of 'postpone verdict'.
(Other definitions for never that I've seen before include "Under no circumstances" , "No way" , "'It's now or - - ' (14 song)" , "' - - Say - - Again': Bond film" , "Do not give up!" .)