The complete Sims 4 Skills List can be found below. All skills gain rates can be boosted if the Sim is experiencing a particular Emotion. Gaining a level means the Sim will perform that action better, succeed more, and generally gain additional actions based on that skill. Working on the skill fills a progress bar that appears above your Sim's head, and when it fills, the Sim gains a level in that skill. Generally skills are gained by performing the actions associated with it: cooking a meal increases the Cooking skill, repairing stuff increases the Handiness skill, and so on.
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