Lock Off is a technique in which the player toggles off their Lock On by pressing L while they are locked on to their opponent. If there are no assist characters or EX Cores to lock onto, the player will then be in a Lock Off state, during which they cannot use any assigned bravery or HP moves that involve a directional input.
However, moves that are assigned to circle or square with no additional directional inputs can be performed while facing in the direction the player is moving towards instead of directly towards opponent. This allows players to use these moves to generate assist meter on whiff without the fear of being blocked by the opponent. It is the single most common use for locking off of the opponent in any match, most notably for Squall.
|Lock Off example with Squall|
Instead of aiming directly towards the opponent, Squall uses Beat fang while locked off to generate assist meter while also creating distance from his opponent.
Golbez can utilise Lock Off to cause his Nightglow HP's Ranged High attack to spawn directly under him instead of under his opponent. It is typically used as an attempt to counteract the opponent's attempt at dashing towards Golbez and hitting him during Nightglow.
Other means of using moves while locked off are far and few in between, such as using Jecht Block to block Kuja's Snatch Blow's second hit that hits from behind.