(From Sax. abere, apparent, notorious; and mord, murder.) Plain or downright murder, as distinguished from the less heinous crime of manslaughter, or chance medley. It was declared a capital offense, without fine or commutation, by the laws of Canute, c. 93, and of Hen. I. c 13. Spelman.
Law Dictionary – Alternative Legal Definition
A spontaneous and malicious murder, obsolete term that was used to distinguish intentional murder from manslaughter.