1. A different way of saying "no" or "that's a bad idea"
2. Anything really, including yes (when high)

Typically said by white people
Rob: "Dude, we could totally smoke behind this new house being built!"
Nick: "Nah nigga nah, THEY KNOW!"
Rob: "Who the fuck are they? You crackhead."
by ScreamingMute August 16, 2011
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