the world > existence and causation > creation > destruction > [noun] > one who or that which destroys > that which ruins a person (2)
spec. colloquial. Something that finishes, discomfits, or ‘does for’ any one; ‘a settler’. In Pugilism, one who gives a blow that ends a fight…
slang. Something which inflicts great damage on a person; something which finishes a person off. Cf. cook, v.1 7. Obsolete.