Ima just tell you the skill times.

Active: Usually skills with the 'Cost' or 'Active' in them, to active these skills you only have to think about using them while thinking of the skills name or saying it out loud, and on rare chances they will activate as a defense mechanism.

Passive: Skills that are always active hence the name passive.

Trigger: Skills that need a special event to happen to active, and usually have the 'Activation requirement' or 'Trigger' in them, some times it can be different. They were thought to be only active and passive skills but trigger was made since some skills had weird things in the, but people still think triggers are passives.

Here is a example for trigger.

Hidden shield Rank: B+ Description: A invisible shield-like object that blocks attacks towards the heart. Trigger: Attacking aiming towards the user's heart

Too be know some skills are in a in between active and trigger so it's pretty weird.

like this

Shalikm Judgement Rank: A Description: Increases user's str by 100: User can temporarily use Skalikm swordsmanship, for 5 minutes. Activation requirement: Shalikm's approval. Cooldown: 5 hours