A male given name; often short for Montgomery; also British slang for a certainty or something guaranteed to happen.
From Norman French 'Montegomery,' meaning 'big mountain.' As a name, it became popular in English-speaking countries and eventually shortened to 'Monty.'
The phrase 'full monty' (everything completely) might come from a 1950s British tailor named Monty Burton, who offered 'full Monty' suits with matching jacket and trousers—or it might not, but the origin is delightfully mysterious.
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