Nothing good is postponed (2,3)
I believe the answer is:
on ice
'is postponed' is the definition.
(I've seen this before)
'nothing good' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'good' becomes 'nice' (similar in meaning).
'o'+'nice'='ON ICE'
(Other definitions for on ice that I've seen before include "Predatory insect" , "Suspended; chilled" , "kept for later" , "Halted for a while" , "one way to serve gin" .)