Leave freezing block entire? That would make no difference (3,2,3)
I believe the answer is:
cut no ice
'leave freezing' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'block entire? that would make no difference' is the wordplay.
I cannot really see how this works, but
'block' could be 'ice' (I've seen this before) and 'ice' is found within the answer.
'make' could be 'cut' (cutting is a kind of making) and 'cut' is found within the answer.
'no' could be 'o' (O resembles 0) and 'o' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for cut no ice that I've seen before include "Blunt skates will" , "Fail to split frozen water and count or nothing" , "Be ineffective" , "Not make any impression" , "Fail to convince" .)