an actual sin which is a grievous offence against the law of God

a sin against any one of the Ten Commandments

a transgression of such severity that it causes a fall from grace, rendering the sinner subject to eternal punishment

a sin committed with a clear knowledge of its guilt, with full consent of the will, and concerning a grave matter; where circumstances allow, every mortal sin must be confessed to a priest otherwise the soul suffers eternal damnation

a serious and willful transgression of God's Law. It involves full knowledge and intent of the will to commit the sin. If left unrepentant, can damn someone to eternal hell.

According to the beliefs of Roman Catholicism, a mortal sin is a sin that, unless confessed and absolved (or at least sacramental confession is willed if not available), condemns a person's soul to Hell after death.

Mortal Sin is an Australian thrash metal band that formed in 1985. The group formed around singer Mat Maurer and drummer Wayne Campbell in Sydney. At first Campbell had attempted to get Maurer into another band called Wizzard but the rest of that band was reluctant to support the idea so the pair struck out on their own, quickly recruiting Wizzard's guitar Keith Krstin, bass player Andy Eftichiou from a band called Judge and a second guitarist Neville Reynolds.