To be knowledgeable or expert in a particular subject
Know Your Onions
Example Sentences
"When it comes to cars, he really knows his onions."
"She knows her onions about computers."
Etymology & History
Origin uncertain, possibly from American English in the 1920s. May reference S.G. Onions, a lexicographer, or simply mean knowing the layers/details.
Word Details
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Region
General British
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Era
Interwar Period
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Language
Mild
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Formality
Informal
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Anglotopia's Dictionary of British English 2nd Edition
British Slang from A to Zed
By Jonathan Thomas
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