Blow-Down is an attack the enemy does to your party characters that knocks them up into the air, makes them lose tension, and then fall onto the ground. Depending on the which enemy and which art the enemy used, Blow-Down will sometimes cause the party to have a Daze status when they stand up again.
Blow-Down is not to be confused with Knock-Back, where an attack pushes the target away a certain distance, during which the target loses control for about a second.
Some enemies have blow-down attacks that just effect the area in front of them. Some enemies have blow-down attacks that attack in a circle around them. An excellent example of which is when a Nebula type monster is low on health, it will self destruct causing a circular blow-down effect. This is responsible for causing many players the frustration of being deprived of the rewards of killing the monster while being humiliated in a Daze state.
Blow-Down attacks can knock your characters off high ledges. If the ledge is sufficiently high, the character can become incapacitated from the fall damage. If the character the player is directly controlling is knocked into an abyss, the battle is lost and the party respawns from the last landmark visited. If this happens to another party member not directly controlled by the player, they will simply re-spawn nearby in a Daze state).