Nothing subtle in reserve (2,3)
I believe the answer is:
on ice
'in reserve' is the definition.
(to put something on ice is to postpone it)
'nothing subtle' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'subtle' becomes 'nice' (nice can mean subtle or precise).
'o'+'nice'='ON ICE'
(Other definitions for on ice that I've seen before include "held back?" , "one way to serve gin" , "Predatory insect" , "In store, preserved" , "Ready to skate" .)