Commodious sense: venial by event (pardoned) vs mortal by event (actually damning)
First commodious use: ‘venial’ for sins actually pardoned through faith and repentance—even if huge in themselves.
‘Mortal’ then marks sins that in fact damn through unbelief and impenitence—Rome’s ‘from the event.’
Latin
XXV. Et primo quidem patiuntur venialia dici peccata quae actu veniam consequuntur, propter peccatoris fidem & resipiscentiam, utut in se gravissima sint: singulari vero quadam ratione mortalia, quae mortem & perditionem aeternam peccantibus reipsa afferunt, propter ipsorum incredulitatem & impoenitentiam. Quod Schola Romana vocat mortale & veniale ex eventu, ut antea observatum fuit.