Time for a full stop (6)
I believe the answer is:
period
This clue is a double definition.
'time' is the first definition.
(period is a kind of time)
'for a full stop' is the second definition.
(US name for a full stop)
(Other definitions for period that I've seen before include "End of story" , "School session" , "Length of time, or a full stop" , "Spell, epoch" , "Duration or interval" .)