Etymology From Middle English dudde (“cloak, mantle, kind of cloth; ragged clothing or cloth”), from Old English *dudda (attested only as personal name Dudda, part of modern English Dudley), akin to Old Norse dúði (“swaddling clothes”), Low German dudel. Possibly borrowed from the Old Norse word and related to dýja (“to shake, tremble”).
1
Informal A device or machine that is useless because it does not work properly or has failed to work, such as a bomb, or explosive projectile.
The only amusing highlight was Gudgeon having managed to exploit U.S. codebreaking efforts to ambush and destroy the submarine I-173, albeit not for the lack of the Mark 14's trying to sabotage the effort, as the torpedo that had hit the sub had refused to detonate; it seemed, however, that the car-crash levels of kinetic energy involved in the dud simply ramming the sub had nonetheless done enough to fatally damage it.2021 December 29, Drachinifel, 21:03 from the start, in The USN Pacific Submarine Campaign - The Dark Year (Dec'41 - Dec'42), archived from the original on 19 Jul 2022:
Alzheimer's Drug Aduhelm Went From Being Hailed A 'Game Changer' To A Dud2024 February 1, Joshua P. Cohen, “Innovation - Healthcare”, in Forbes:
At the end of the day, the vast majority of primary schools are vibrant, friendly places and you may struggle to choose one because they all seem so great. Primary schools tend to have the feelgood factor. If you just aren't feeling it, this one's probably a dud.2014 September 23, A teacher, “Choosing a primary school: a teacher's guide for parents”, in The Guardian:
"Now you can't fool me. Tom, I'm not one o' those duds that pay you a thick 'un for an hour in the dark."1925 July – 1926 May, A[rthur] Conan Doyle, “(please specify the chapter number)”, in The Land of Mist (eBook no. 0601351h.html), Australia: Project Gutenberg Australia, published April 2019:
4
Informal A lottery ticket that does not give a payout.
5
Informal, Obsolete Clothes, now always used in plural form duds.
Etymology From Middle English dudde (“cloak, mantle, kind of cloth; ragged clothing or cloth”), from Old English *dudda (attested only as personal name Dudda, part of modern English Dudley), akin to Old Norse dúði (“swaddling clothes”), Low German dudel. Possibly borrowed from the Old Norse word and related to dýja (“to shake, tremble”).
1
Useless; failing; ineffective.
[…] they're flying in the duddest of dud weather to hold the Germans back.2019, Max Hennessy, The Bright Blue Sky: