involuntary dismount
A fall, typically off of something being ridden, such as a bike, motorcycle, or horse. Did you her about Tara? Her involuntary dismount yesterday earned her a trip to the OR and two months in a cast. I gave up motorcycles after one too many involuntary dismounts.
involuntary dismount
n. falling off a bike or motorcycle. He impacted a monolith and suffered an involuntary dismount.