noun Date: 15th century a sin (as murder) that is deliberately committed and is of such serious consequence according to Thomist theology that it deprives the soul of sanctifying grace
MORTAL SIN
Meaning of MORTAL SIN in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012