A martial artist was a person who practiced martial arts, a form of melee combat. Many do not use any weapons at all, but have trained their body to be a living weapon. However, there were some martial arts forms that did use some weapons, such as the Stava form of the Noghri, and the Petranaki form of the Geonosians.
There were also schools that trained force-sensitive martial artists on how to combine the use of the Force into their combat form. Both the Jedi and the Sith monitored these martial arts schools for potential recruits, knowing that ideal candidates could be found among these exceptional individuals who focused their mind and body in harmony with the Force.