1.  mayhem(n = noun.act) - the willful and unlawful crippling or mutilation of another person;
is a kind of crime, criminal offence, criminal offense, law-breaking, offence, offense

2.  mayhem(n = noun.act) havoc - violent and needless disturbance;
is a kind of disturbance

1.  The maiming of a person by depriving him of the use of any of his members which are necessary for defense or protection. See Maim. [1913 Webster]

2.  Violent disorder, especially such as causes serious harm to persons or damage to property. [PJC]

mayhem, n.
1 violent or damaging action.
2 hist. the crime of maiming a person so as to render him or her partly or wholly defenceless.

Etymology:
AF mahem, OF mayhem (as MAIM)