A punish is a term for hitting the opponent during the recovery of their attack. It can also be used to describe when cutting off false sequences of attacks.
Description[]
In Street Fighter, recovery refers to the amount of time that a character has before they return to an actionable state, following a particular action. When an attack comes on contact with an opponent, the recovery of the defender and the recovery of the attacker result in a period where both players are unable to act. Depending on the attack's hitstun or blockstun, an attack can be advantageous for a mixup or combo if the attacker recovers first, or disadvantageous and potentially punishable if the defender recovers first.
Generally attacks that are punishable on block include sweeps, reversals, Super Combos, and anti-airs. There also exist rare cases of moves that are punishable on hit, generally from normal attacks that are meant to be special-cancelled or spaced out, such as slides or divekicks with particularly long active frames. These attacks can be spaced to hit on a later active frame or with an extended hitbox to make them less punishable, safe, or even advantageous on block. How punishable an attack is can vary depending on the defender, such as Zangief's being able to punish some -5 attacks with a Screw Piledriver, while other characters may not be able to reach or hit in time.
Some attack sequences do not keep the defending character in Block Stun throughout the whole sequence, using an attack that can interrupt the sequence can also be considered a punish. In most cases not much damage can be done when cutting off due to only lighter attacks being fast enough for the job or 1-hit invincible specials.
In Street Fighter 6, punishes are a core part of the gameplay in the form of Punish Counters. Attacks that hit during an opponent's recovery frames gain an extra four frames of advantage and deplete part of the opponent's Drive Gauge, along with certain moves gaining other properties similar to Crush Counters. Throws also gain a massive 70% damage bonus, gain 40% of a Super Art gauge, remove one bar of opponent's Drive Gauge, and cause a hard knockdown.
Tactics[]
Learning to punish optimally is important in Street Fighter games. Not learning to punish attacks can mean opponents can get away with tactics that are unsafe and seem to be undefeatable. Technically speaking any hit for an unsafe attack can be considered a punish. An optimal punish refers to a sequence that maximizes damage or prioritizes other factors, such as corner carry, mixups, or knockdowns. Knowing how negative an attack is can also allow for even stronger starters, further increasing optimization.
The other punish type is interrupting. This refers to taking advantage of attack sequences that have a gap in blockstun and performing an action that would interrupt the next attack in the sequence. Usually the damage possible isn't high, but this discourages opponents from trying sequences that can lead to chip damage or other otherwise advantageous tactics for them.
Whiff Punish[]
Another subset of punishing is "whiff punishing". Rather than hitting an opponent following their attack making contact, whiff punishes occur when attack doesn't make contact at all and the attacker remains in recovery afterward. Attacks with extended hurtboxes in recovery or done with poor spacing are more prone to be whiff-punished. Moving in and out of range of the opponent can allow for whiff punishes if they misjudge whether or not an attack can hit. It should be noted when punishing extended hurtboxes the physical positioning of the opponent can be further away once hit than initially appears.