Second time for wise guy (4)
I believe the answer is:
sage
'wise guy' is the definition.
(I've seen this in another clue)
'second time' is the wordplay.
'second' becomes 's' (common abbreviation).
'time' becomes 'age' (an age is a period of time).
's'+'age'='SAGE'
'for' is the link.
(Other definitions for sage that I've seen before include "Wise woman" , "Man of wisdom" , "Clary" , "cheesemongers associate with Derby" , "Salvia" .)