Cut him dead

What's the origin of "cut him dead" or "cut her dead" and what does it mean exactly?

To cut someone dead means to "cut" them socially, that is, snub them, pretend not to see them or know them ("Do I know you?"), turn your back on them, etc. The word "dead" just adds emphasis. I don't think anyone has died of a social snub, but many have have their social lives wounded.

I've been told that the cliques formed by 13-year-old and 14-year-old girls sometimes employ snubs of this variety, although I don't know how often the word "cut" is used.

The Oxford English Dictionary includes this use of the verb "cut" (no. 33 in their list of definitions), and quotes an example of it from the seventeeth century.
SS