Game concept
Absolute Tribal Authority
The game also links it as Absolute.
From the game's encyclopedia
Absolute Tribal Authority is the highest level of Tribal Authority. Vassals have a -30 Opinion penalty towards their Liege.
At this level, in addition to the effects of Limited and High Tribal Authority, rulers can now settle and become Feudal.
Unreformed Tribal Pagan rulers require this law to reform their Faith.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Absolute Tribal Authority is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Absolute Tribal Authority is the highest level of Tribal Authority." It is part of Tribal Authority. The game also links it as Absolute. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.