Nick single, not out (3,2)
I believe the answer is:
run in
'nick' is the definition.
'single not out' is the wordplay.
'single' becomes 'run' (cricket).
'not out' becomes 'in' ('in' is the opposite to 'out').
'run'+'in'='RUN-IN'
(Other definitions for run in that I've seen before include "Brush" , "Quarrel; set-to" , "Pick up" , "Quarrel; arrest" , "Approach -- disagreement" .)