Still is returned with a fast time (6)
I believe the answer is:
silent
'still' is the definition.
(I know that still can be written as silent)
'is returned with a fast time' is the wordplay.
'returned' shows that the letters should be reversed in order.
'with' is a charade indicator (letters next to each other).
'a fast time' becomes 'lent' (Lent is a time for fasting).
'is' written backwards gives 'si'.
'si'+'lent'='SILENT'
(Other definitions for silent that I've seen before include "Like early films" , "Enlist (anag) - mum" , "Free from noise" , "Strange and astonishing thing" , "Soundless" .)