ruin

1. (countable, sometimes in the plural) The remains of a destroyed or dilapidated construction, such as a house or castle.Examples: "The Veian and the Gabian towirs shall fall, / And one promiscuous ruin cover all; / Nor, after length of years, a stone betray / The place where once the very ruins lay."; "The labour of a day will not build up a virtuous habit on the ruins of an old and vicious character."; "A canister of flour from the kitchen had been thrown at the looking-glass and lay like trampled snow over the remains of a decent blue suit with the lining ripped out which lay on top of the ruin of a plastic wardrobe."countablein-pluralsometimes

2. (uncountable) The state of being a ruin, destroyed or decayed.Examples: "The monastery has fallen into ruin."uncountable

3. (uncountable) Something that leads to serious trouble or destruction.Examples: "Gambling has been the ruin of many."; "The errors of young men are the ruin of business."; "The Bat—they called him the Bat.[…]. He[…]played a lone hand,[…]. Most lone wolves had a moll at any rate—women were their ruin—but if the Bat had a moll, not even the grapevine telegraph could locate her."uncountable

4. (obsolete) A fall or tumble.Examples: "His ruin startled th’ other steeds."countableobsoleteuncountable

5. (uncountable) Complete financial loss; bankruptcy.uncountable