Game concept
Untaxed Jurisdiction
The game also links it as Untaxed Jurisdictions, Untaxed.
From the game's encyclopedia
An Untaxed Jurisdiction is a Tax Jurisdiction with Taxpayers, but without a Tax Collector. This means that the assigned Taxpayers will not give any Taxes or Levies to their Liege.
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.
Untaxed Jurisdiction is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "An Untaxed Jurisdiction is a Tax Jurisdiction with Taxpayers, but without a Tax Collector." It is part of Tax Jurisdiction. The game also links it as Untaxed Jurisdictions and Untaxed. Patch 1.20.1.2, from game/common/game_concepts/03_fp3_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/03_fp3_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.