A slang phrase meaning "To have a physical accident", often a serious one. It applies especially to accidents in which you fall down or trip and fall. In general, it means to to be brought low by gravity and momentum. It can mean to lose control whilst travelling at speed and colide with a stationary object or impact the ground.

This phrase is generaly applied to people and sometimes to cyclists. It is less frequently applied to more more mechanised forms of conveyance. It is less frequently applied to abstract derailments.