Game concept
Skills
The game also links it as Skill.
From the game's encyclopedia
The Skills of a Character measure how good they are at various things.
The five main skills are: Diplomacy, Martial, Stewardship, Intrigue, Learning.
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.
Skills is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "The Skills of a Character measure how good they are at various things." It covers Diplomacy Skill, Martial Skill, Stewardship Skill, Intrigue Skill, Learning Skill and 2 more. The game also links it as Skill. 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.