This time is not the first (6)
I believe the answer is:
second
This clue is a double definition.
'this time' is the first definition.
(unit of time)
'not the first' is the second definition.
(not the first but the second)
'is' is the link.
(Other definitions for second that I've seen before include "Position of runner-up" , "Silver medal position" , "Mo" , "Support, assist" , "Between first and third" .)