The equivalent of a hangover, but when you've been really lean the night before. Characterised by a lazy fatigue, forgetfulness, and a mild desire for another joint (See Wake n Bake.)
Keifer: "Dude, I feel a little hungover, I only had three beers."
Neal: "You're having a lean over, man. You're only halfway there, you might as well have gotten completely smashed."
n. A rare phenomena, similar in severity to a hangover, but occurring on the second day after heavy drinking with a strangely deceiving, asymptomatic day in between.
Ralph was power-drinking at the party on Friday nightto the point where he almost passed out. He was up early on Saturday claiming no ill effects, only to suffer a debilitating leapover all day Sunday.