Attack is one of the 5 attribute stats that determine the success or failure of combat.
The other attributes are Damage, Armor, Defense, and HP.
Attack points allow a player to actually hit the target. The more attack a player has, the more likely that player will actually score a hit with each swing. Attack is countered by defense. If a player has less attack than the opponent's defense, the player is unlikely to score a hit on the target.
A player can decrease an opponents defense with the Dark Curse buff.