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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Refers to Errol Flynn's popularity with women in the 40's. His ability to attract women was well known throughout the world. ('In like flint' is also used.)
In Dante's Inferno, the ninth circle of hell is the centre where the worst punishments are found, so it is used idiomatically for something that couldn't get worse.