Nothing new, I left (3)
I believe the answer is:
nil
'nothing' is the definition.
(eg nil is zero in football)
'new i left' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'left' becomes 'L' (common abbreviation).
'n'+'i'+'l'='NIL'
(Other definitions for nil that I've seen before include "Nothing found in senility" , "Lacking value" , "Nothing, naught" , "none" , "There's nothing left" .)