When a Jedi Knight began their independent studies separate from their former Jedi Master, they had the option of choosing from three classes of Jedi: the Guardian, Consular, and Sentinel. A brute of the the Jedi Temple Security Force was a Guardian who pursued the specialization of Peacekeeper based on Coruscant.
Stationed within the walls of the Temple Precinct, Temple brutes typically were physically intimidating, and preferred to use double-bladed lightsabers when defending their home. Unlike the snipers, brutes worked in close-combat situations.
The rank of Temple brutes dates as far back as the Ruusan Reformation and the reorganization of the Jedi Order by Grand Master Fae Coven. Codifying the ranks and duties of the Jedi in her handbook called The Jedi Path: A Manual for Students of the Force, the term was used until the dissolution of the Order in 19 BBY. When the Supreme Chancellor of the Galactic Republic was revealed to be a Sith Lord, he quickly ordered the Grand Army of the Republic to turn on the Jedi before they could remove the Sith from office. Darth Vader, the Sith Lord Darth Sidious' new apprentice, led the 501st Legion against the Temple, conducting Operation: Knightfall as part of Contingency Order 66. The brutes of the Temple defended it valiantly against the Sith and his army but were vastly outnumbered. By the end of the night, the brutes were largely, if not completely, routed.
Leland Chee describes the term "Jedi brute" as a gameplay term for a type of enemy, as opposed to an in-universe term used by the Jedi. This was later superseded by their inclusion in Daniel Wallace's The Jedi Path: A Manual for Students of the Force.