Okizeme (起き攻め) is a term borrowed from the Japanese fighting game community which stems from the words oki (起き) meaning "to get up" and zeme (攻め) meaning "attack".
Okizeme, often shorted to "oki", describes a situation in which one player attacks their opponent while the opponent's character is getting up off of the ground from being knocked down.
This works because the player whose character is standing is able to act while the other character cannot. This creates a situation in which the standing player can set up meaties, safe jumps and more that the other player is forced to deal with. The exact manner in which oki is applied varies wildly between characters and games, but at its core the concept is always the same. The attacker will attempt to mix up the defender or force them to take chip damageDamage incurred when blocking an attack. Typically, only Special Attacks and Super Attacks have chip damage, but there are exceptions..