When someone has smoked a certain amount of weed, they give off a green fuzzy glow which to the untrained eye makes them look dirty.
Person 1: Hey man you look really dirty

Person 2: That's weird, I showered this morning

Person 1: How much weed have you smoked today?

Person 2: About an ounce man

Person 1: Ah, probably the weed glow.
by ycsiemanymiH November 3, 2010
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