Game concept · All Under Heaven
Barter
The game also links it as Bartering, Bartered, Barters.
From the game's encyclopedia
Wanua Rulers can raise Barterers to gain Gold through peaceful means. Bartering works similarly to Raiding, with some key differences — it is not a Hostile action, and you need Barter Goods.
You need 2 Barter Goods to gain 1 Loot from a Holding. If you have too little, nothing will happen.
Bartering is a friendly action, and the targeted holding will gain Recently Bartered upon completion. Unlike Raiding, you can freely Barter in the lands of your Tributaries and Suzerain.
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.
Barter is an entry of Crusader Kings III's in-game encyclopedia (All Under Heaven). The game explains it: "Wanua Rulers can raise Barterers to gain Gold through peaceful means." It covers Barterer and Barter Goods. The game also links it as Bartering, Bartered and Barters. 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.