Q: How did “duds” become slang for clothes?
A: We wouldn’t describe the use of “duds” for clothing as slang. The five standard dictionaries we’ve checked list it as informal or include it without comment—that is, as standard English.
In fact, the word has referred to clothes for hundreds of years, since the Middle Ages, when a “dudde” was “a cloak or mantle,” according to the Chambers Dictionary of Etymology.
The earliest example we could find is from a 1307 entry in Boldon Buke, a survey ordered by Bishop Hugh Pudsey of church possessions in Durham, England:
“xxvj duddis emptis ad pauperes” (“26 duds bought for the poor”).
And here’s a felonious example from Lanthorne and Candle-Light, a 1609 pamphlet by the Elizabethan dramatist Thomas Dekker:
“We will filch some duddes: we will filch some clothes.”
Chambers says the word is “of uncertain origin.” The English philologist Walter William Skeat has said it’s probably of Scandinavian origin, though preserved only in dúða, an Icelandic word for swaddling clothes.
In the early 1500s, the English plural “duds” also came to mean ragged clothing, according to the dictionary, and in the early 1900s the singular “dud” took on the sense of an inefficient or useless person or thing.
Here’s an example from the Jan. 28, 1908, issue of the Westminster Gazette for the useless sense: “A ‘dud’ car is a worthless contraption.”
In World War I, Chambers says, the word “dud” came to mean “a shell which failed to explode; hence, failure.”
The earliest example for the military sense in the Oxford English Dictionary is from Between the Lines, a 1915 book about the war by Boyd Cable, pen name of Ernest Ewart: “One of these [shells] was a dud an’ didn’t burst.”
The OED’s first example for “dud” used in reference to a human failure is from the Sept. 1, 1920, issue of Punch: “He … has … been irritated by his school-boy son derisively addressing him as an ‘old dud.’ ”
Note: Although standard dictionaries accept “duds” (used to mean clothes) as informal or standard English, the OED describes it as slang or colloquial. However, the OED notes that its entry hasn’t been fully updated.
from Grammarphobia http://www.grammarphobia.com/blog/2015/12/duds.html