Motorcycle roadracing term used to describe a crash in which the bike is leaned over while cornering and flips back up towards the outside (i.e. the high side). A high side usually occurs when rear wheel traction is suddenly lost and the rider's panic causes him to abruptyl close (chop) the throttle. As a result, the rear wheel suddenly and forcefully regains traction, violently flipping the bike away from the direction of lean and throwing the rider skyward. Most racing injuries occur as a result of a high side since the rider has much further to fall.

The flip side of this (no pun intended) is a low side crash. These crashes are usually minor since the rider falls off much closer to the ground.
That clueless squid lost the rear halfway through Turn 7, chopped the throttle and high sided his brand new, chromed out R1 into the hay bales.
by razer December 22, 2006
"man i saw this nasty ass hoe, i gave her the high side"
by ? April 20, 2003
When a motorcycle throws the rider off going over the handle bars.
He got into a tank slapper and went over the high side.
by John Stewardson January 17, 2004
The act of behaving in a manner abnormal to one's normal decorum, therein suggesting or implying superiority. See condescending.
Yesterday she was sweatin' me; now she's high siding since her girls are around.
by Osakwedagr8 August 3, 2009
In terms of motorcycles "High siding" is where a sliding bike's tires gets traction and flips. As you go hard into a turn instead of the bike slipping out under you it bites very hard and does sort of a lever action along its wheel base.
I broke the head on my bike when i high sided that turn last year. Lucky I didn't kill myself.
by blake April 30, 2004
When someone disses you, gets in your grill or is just an all around asshole to you.
Man, why you high sidin me? I didn't know she was your sister.
by Grouch April 20, 2004
Someone who has had their sideburns shaved very high, or shaved off completely
What happened to his sideburns?
Someone gave him a high-side rider.
Was he asleep at the time?
No, he thinks it looks good.
by LaneG July 5, 2011