A type of Verbal that keeps you from using one of your arms (or even legs) for a duration of time. From the Accelerant core rules:

"One limb becomes useless. An arm must hang at your side and cannot be used for any game ability. A leg becomes unusable. You must go down on one knee - you cannot hop. You may crawl using your other limbs. A Maim effect will last for the duration of the event. If a Maim effect is delivered by a melee or missile attack, the limb struck will be affected. If a Maim effect delivered by a melee or missile attack strikes the torso then the Maim effect is ignored. If a Maim effect is delivered by a packet, the attacker can include the limb in the verbal. For example, a caster might call out "Maim Right Leg by Fire." If the limb is not specified, then the subject may choose one limb that is not already affected by a Maim. Maim only works on arms and legs."