The present participle of 'cady,' an obsolete or dialectal term meaning to twist, turn, or move in a winding manner.
From Middle English caden, possibly related to cad- roots. This is primarily a historical or dialect term with unclear exact origins.
This word is so obscure it barely appears in modern dictionaries, but it shows how many old English verbs for movement have completely disappeared—we've basically simplified our action vocabulary dramatically.
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