A Mat Rempit is a Malaysian term for "an individual who participates in immoral activities and public disturbance with a motorcycle as their main transport", usually involving underbone motorcycles, colloquially known as Kapcai, or scooters. Mat Rempits are not involved in street racing but rather go against each other for cheap thrills and to rebel against authorities while some of them perform stunts for fun, such as the wheelie, superman (lying flat on the seat), wikang, and scorpion (standing on the seat with one leg during a wheelie).
The word "Rempit" comes from "ram(rev)-it" (ram the throttle). According to Kamus Dewan, the definition of "Rempit" is "the act of whipping with a cane". An alternative source of the word is derived from the noise made by a 2-stroke motorcycle. "Mat" is a Malay slang term used to address or to refer to a male person who is usually of Malay descent but is generally used derogatorily.
Mat Rempits usually travel in groups and create disturbance in bustling city centres on weekend nights. Mat Rempits are usually associated with gangsterism, gang robbery, street fighting, assault, vandalism, theft and bullying. Most motorcycles used by the Mat Rempits do not meet standard specifications, or have been modified extensively for greater speed, or just to make the exhaust noisier.
Additionally, most Mat Rempits do not have valid motorcycle licenses, do not pay road taxes, and ride stolen motorcycles. A growing number of housing estates have also been turned into racing tracks. It is estimated that there are about 200,000 Mat Rempits in Malaysia.
In April 2009, Malaysia's Inspector-General of Police Tan Sri Musa Hassan said that the Mat Rempit had become violent and brazen instead of just being a public nuisance. He said "We have to come down hard on the Mat Rempit who have started to become involved in robberies, snatch thefts and are even attacking innocent road users and we also need to use harsh tactics to catch the Mat Rempit that try to runaway from the roadblocks ." He also added that "Parents must be more responsible and should not allow their underage children to drive cars or ride motorcycles"
Mat Rempits often end up being hospitalised after they fail to perform their actions or stunts such as 'superman', 'spider' and many more. Every weekend, around 10 people are hospitalised after being involved in accidents when riding motorcycles at high speed.