ruin · noun /ˈruː.ən/
ruin (REMAINS)
B1 C the broken remains that are left from an old building after it has been destroyed
Dictionary example:
Thousands of tourists wander around these ancient ruins every year.
Learner example:
After that I'm going to travel to Luxor and see [the] ruins. (Preliminary English Test; B1; Russian)
be/lie in ruins
C1 to be in a very bad state
Dictionary example:
The city lies in ruins.
Learner example:
When my grandparents were young, Germany lay in ruins. (Certificate in Advanced English; C1; German)
ruin (LOSING EVERYTHING)
C2 U when someone loses everything such as all their money or their job
Dictionary example:
The collapse of the bank has left many people in financial ruin.
Learner example:
He started his first business some time ago which led to financial ruin. (Certificate of Proficiency in English; C2; Lithuanian)
ruin · verb T /ˈruː.ən/
ruin
B2 to spoil or destroy something completely
Dictionary examples:
They were late and the dinner was ruined.
Her injury ruined her chances of winning the race.
Huge modern hotels have ruined this once unspoiled coastline.
Learner example:
But she didn't keep her promise and she ruined my life. (First Certificate in English; B2; Spanish)