Meaning of “ruin” - Learner’s Dictionary

ruin

noun uk us /ˈruːɪn/
DESTRUCTION [ U ]

the destruction of something:

Fonthill Abbey fell into ruin 10 years after it was built.
BROKEN BUILDING [ C ]

B1 the broken parts that are left from an old building or town:

Thousand of tourists wander around these ancient ruins every year.
LOSING EVERYTHING [ U ]

a situation in which someone has lost everything such as all their money or their job:

The collapse of the bank has left many people in financial ruin.
be/lie in ruins

to be in a very bad state:

The war left one million people dead and the country in ruins.

(Definition of “ruin noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)