The act of smoking marijuana with at least one other person. Used to refer to the original use of Tobacco by Native American Chiefs in North America. Now used when associated with marijuana, not tobacco.
Hey man, do you wanna chief up with me later?

Hey lets all chief up at the after party

Yo - bro, don't be chiefing up in the bedroom - do that shit in the living room - and share it.
by SayWhat99 December 24, 2011
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