The ground finish is a special assassination kill in Assassin's Creed IV Black Flag.
How to Get A Ground Finish
You can only get a ground finish when your target is on the ground already.
This happens when your target's target stuns him right before an assassination.
This will leave your opponent weakened and temporarily unable to move.
While the enemy is kneeled over on the ground, run up to him and press O or B, on PlayStation 4 or Xbox One respectively, to execute a ground finish.
Points Value
The standard points value for the ground finish is 1 point.