in a way that is well-known for being bad or negative; famously (usually in a negative sense).
From 'notorious' (Latin 'notorius' from 'notus' meaning 'known'), plus '-ly' for the adverbial form, literally meaning 'in a known way.'
Unlike 'famous,' being 'notorious' means everyone knows about your failures—it's how language lets us distinguish between being known for good versus being known for scandal.
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