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.

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Company. All rights reserved.