When you're smoking weed and you take a hit and you hold in 100% of the smoke from the inhale, exhaling *zero* smoke from the hit. Done in order to get maximum effect from the weed. Requires great skill and is worthy of respect from other smokers.
"Yo I was ripping a B with Joey Fatone the other day and he was totally zeroing every time ... insane!"
by Ol' Prospector October 18, 2009