In a manner showing that one is fully persuaded, certain, or convinced of something; with firm belief or certainty.
From 'convinced' (past participle of convince, meaning persuaded) plus '-ly' (in what manner). Convince comes from Latin 'convincere' (to overcome by proof).
Convincedly is almost never used in modern English—speakers prefer 'firmly' or 'certainly'—but when it does appear, usually in older literature or formal writing, it signals absolute, unshakeable certainty, suggesting the person has moved beyond mere belief into deep conviction.
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