Of good quality; seemly, proper (archaic, dialectal, especially Northern English).
From Middle English and Old Norse influences, possibly related to 'grade' in the sense of 'suitable' or 'fitting'. The '-ly' suffix creates an adjective. Archaic and primarily dialectal.
Medieval Northern English people said 'gradely' for things done 'proper-like'—it's survived in place names and dialects, but mostly disappeared because 'proper' just sounded better to modern ears.
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