cut (one) dead
To totally ignore someone, usually out of anger or displeasure. I was hoping to reconcile with Mandy today, but when I approached, she just cut me dead.
cut someone dead
Pretend not to see or recognize someone, as in "Any fellow was to be cut dead by the entire school" (Benjamin Disraeli, Vivien Grey, 1826). This idiom, in the first half of the 1600s, began as to cut one; in the early 1800s dead was added for greater emphasis.
cut someone dead
BRITISHIf you cut someone dead, you deliberately ignore them or refuse to speak to them. I belonged to the same golf club as my father-in-law and if I ever saw him at the clubhouse he'd cut me dead. There were times when she would cut you dead.
cut someone dead
completely ignore someone.