George Zimmerman Fight -- CANCELLED ... Promoter Gets Cold Feet

George Zimmerman will not be going toe-to-toe with DMX in a celebrity boxing event ... and the promoter says it's because his conscience finally kicked in.

The promoter for the event took to Twitter Saturday afternoon to officially cancel the event ... and said he finally realized there's "more to life then money."

The promoter adds, "Just looked at my son and daughter today wow I'm so lucky those people must be in so much pain ... all you people are right."

Unclear exactly what he meant by "those people" ... but probably a poor choice of words.