Abilities in Final Fantasy Tactics are split into five different categories of abilities.
List of abilities
Action abilities are combat abilities, the unit's mandatory job ability appears in the first slot; while the second slot may be assigned any action ability the unit has learned.
Each unit can only equip one reaction ability. Except for Parry and Reflexes, which provide passive boosts to evasion, reaction abilities only activate when their trigger condition is met, and the chance for activating depends on the user's Bravery stat in percentage: the braver the unit the higher the chance.
Each unit can only equip one support ability. Support abilities usually only let a character equip things that their current job will not allow, though they do provide abilities that can protect them in certain circumstances, as well as provide some stat boosts.
Each unit can only equip one Movement ability. Movement abilities allow units to move across battlefields much easier than they would usually be able to without them.
Recruitable monsters use different abilities than those mentioned above.