Snub old churl does — out of order! (4-8)
I believe the answer is:
cold-shoulder
'snub' is the definition.
(synonyms)
'old churl does out of order' is the wordplay.
'out of order' is an anagram indicator.
'old'+'churl'+'does'='oldchurldoes'
'oldchurldoes' is an anagram of 'COLD-SHOULDER'.
(Other definitions for cold-shoulder that I've seen before include "Give (someone) a rebuff" , "Treat with indifference" , "Snub" , "Cut, ignore" , "Brush off" .)