This
database is a comprehensive collection of all the American idioms and slang available.
American Idioms are many and varied. We hope you enjoy our collection. We are adding more all the time.
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If someone escapes scot free, they avoid payment or punishment. 'Scot' is an old word for a tax, so it originally referred to avoiding taxes, though now has a wider sense of not being punished for someone that you have done.
If you're in uncharted waters, you are in a situation that is unfamiliar to you, that you have no experience of and don't know what might happen.
('Unchartered waters' is an incorrect form that is a common mistake.)