A swordmaster was a melee warrior who was proficient in the use of bladed weapons, such as vibroweapons or lightsabers. A swordmaster was constantly training to better his skills in combat. It took years of training and practice to become a swordmaster.[source?]
An example of a Jedi swordmaster was Mace Windu, considered as such because he was a master of all form of lightsaber combat and due to his mastery of Vaapad, which he created.  He was equal to Count Dooku and surpassed only by Yoda himself in skill among the Jedi and even managed to disarm Darth Sidious, although he only managed such a feat because he sensed Anakin's fear.
Cin Drallig, Sora Bulq and Grand Master Yoda were also considered swordmasters. All three of them had mastered every known form of lightsaber combat and Sora was known for helping Mace Windu develop his Vaapad fighting style. Also, all three became lightsaber instructors to many younglings. Yoda was considered to be the greatest swordmaster of his time, surpassing even Mace Windu, Count Dooku and Darth Sidious. 
Kreia demonstrated a great deal of practical knowledge of the various lightsaber forms through her instruction of the Jedi Exile during their journey. She was a practitioner of telekinetic lightsaber combat, and fought with it on a never-before-seen scale. She had the ability to fight with three lightsabers at once, holding each aloft with the Force, making them float and appear to fight with a will of their own. It should be noted, however, that this tactic was an act of desperation, as Kreia had lost both of her hands in previous engagements.
Kas'im was a Dark Lord of the Sith during the New Sith Wars and served as the blademaster at the Sith Academy on Korriban. During his life he mastered every form of lightsaber combat, and proved comfortably effective with any blade type, be it one single, one double, or two single blades. He was the one who trained Darth Bane in the art of lightsaber combat, but was later killed by his former apprentice - not by lightsaber, but by a superior command of the Force.
Darth Tyranus was once a Jedi Master who fell to the dark side and became the Sith apprentice to Darth Sidious. Dooku was a consummate practitioner of Form II: Makashi. He was regarded by many as one of the greatest duelists of his time, on par with Mace Windu who himself was considered by many as second only to Master Yoda.
Darth Sidious was the greatest and most skilled Sith swordmaster, as he has mastered all the seven lightsaber forms, all their stances and techniques and is capable of using each form equally effective ambidextrously. Indeed, he had proven to be capable of competing with Mace Windu and even Grandmaster Yoda, altough he was on the verge of losing against the latter. In fact, Mace was only able to defeat Sidious because he had sensed Anakin Skywalker's fear.
- Star Wars: Knights of the Old Republic
- Star Wars: Knights of the Old Republic II: The Sith Lords
- Darth Bane: Path of Destruction
- Darth Plagueis
- Shatterpoint (novel)
- Yoda: Dark Rendezvous
- Labyrinth of Evil
- Dark Lord: The Rise of Darth Vader
- The New Jedi Order: Dark Journey (Mentioned only)
- Fate of the Jedi: Backlash (Mentioned only)
- "Fightsaber: Jedi Lightsaber Combat"—Star Wars Insider 62
- Jedi vs. Sith: The Essential Guide to the Force
- Knights of the Old Republic Campaign Guide (as Master Duelist)
- Star Wars: The Clone Wars: Episode Guide