Rebellion

A rebellion is an organized uprising against a sovereign or liege, with the goal of overthrowing the established authority.

In the Seven Kingdoms, it is considered a serious crime and an act of treason and oathbreaking.

Major rebellions

 * The Reyne Rebellion was an uprising localized in the Westerlands, in which House Reyne of Castamere sought to overthrow its overlord, House Lannister of Casterly Rock. It resulted in the complete elimination of House Reyne and the destruction of Castamere at the orders of Tywin Lannister.
 * Robert's Rebellion was a major uprising against the royal house that turned into civil war as it involved eight of the nine great houses of Westeros. Houses Baratheon, Stark, Arryn and Tully rebelled against House Targaryen, which was supported by Houses Tyrell and Martell. The tide of war turned against the royal house after the Battle of the Trident while the fate of the royal family was sealed when House Lannister joined the rebels and carried out the Sack of King's Landing. It resulted in the elevation of Robert Baratheon to the Iron Throne.
 * The Greyjoy Rebellion was an uprising led by Balon Greyjoy, Lord Reaper of Pyke, who crowned himself King of the Iron Islands with the goal of seceding his domain from the Seven Kingdoms and restoring the ironborn's Old Way. It resulted in defeat of the rebels and the cementing of Robert's authority.
 * The War of the Five Kings involves several rebellions against the Iron Throne. Both the North and Iron Islands rebel against King Joffrey with the goal of independence. In the meantime, both Renly and Stannis Baratheon are held as rebels and pretenders as they both lay claim to the crown in defiance of Joffrey, who is held as the rightful heir of the late Robert.