“Mayhem” is the act of dismembering or disfiguring another person so as to weaken his ability to defend himself. It is a medieval term (surprise!) coming from the Anglo-Norman maihem or injury. It was originally both a noun and a verb. Prosecutors would bring a charge of mayhem by stating that the defendant “feloniously did mayhem” the victim. By the latter part of the 19th Century, the verb form gave way to the closely-related maim.
One is tempted to ask: wouldn’t any dismemberment weaken one’s defenses? Well, that’s not the way the law sees it. Traditionally, it was mayhem to chop off a limb, but not an ear or a nose because, as Blackstone blandly put it, “they can be of no use in fighting.” Needless to say, lawsuits over repetitive stress injuries didn’t get very far in the Middle Ages.