1 definition by kittybaby7

fucking under the influence. having sex while also experiencing the effects of drugs, alcohol, etc. FUI is the 8th deadly sin and is punishable by a 6 month suspension of your fucking license.
Dude I don't remember her at all...I must have been FUI, I don't even remember her name.
by kittybaby7 June 17, 2007
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