Notice time traitors wasted for manager (13)
I believe the answer is:
administrator
'for manager' is the definition.
(I've seen this before)
'notice time traitors wasted' is the wordplay.
'notice' becomes 'ad' (both can mean an advertisement).
'time' becomes 'min' (short for minute).
'wasted' indicates anagramming the letters.
'traitors' with letters rearranged gives 'istrator'.
'ad'+'min'+'istrator'='ADMINISTRATOR'
(Other definitions for administrator that I've seen before include "Manager, controller" , "Runner" , "One managing business affairs" , "Official organiser" , "One who manages or directs" .)