Game concept

Banishment Reason

The game also links it as Banishment Reasons.

From the game's encyclopedia

A Banishment Reason gives a Liege the opportunity to freely Banish any subject they have in their Dungeon. They are most often gained from the subject being a Criminal.

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.

Banishment Reason is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Banishment Reason gives a Liege the opportunity to freely Banish any subject they have in their Dungeon." The game also links it as Banishment Reasons. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.

for a guide, post or blog

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.