Rebuff or spurn (4)
I believe the answer is:
snub
I believe this is a double definition.
'rebuff' is the first definition.
(I know that rebuff can be written as snub)
'spurn' is the second definition.
(I know that snub is a more specific form of the action spurn)
(Other definitions for snub that I've seen before include "Rebuff, spurn" , "Cut; ignore" , "Slight - short and blunt - humiliation" , "Ignore totally" , "Spurn; (of nose) turned up at the end" .)