Dud

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From Middle English dudde(“cloak, mantle, kind of cloth; ragged clothing or cloth”) [1], from Old English *dudda (attested only as personal name Dudda, modern English Dudley), akin to Old Norse dúði(“swaddling clothes”), Low German dudel.

etymonline

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dud (n.)

1825, "person in ragged clothing," from duds (q.v.). Sense extended by 1897 to "counterfeit thing," and 1908 to "useless, inefficient person or thing." This led naturally in World War I to "shell which fails to explode," and thence to "expensive failure."