I have added fake etymology to my mini ebook Clichés: A Dictionary of Received Ideas (only £1.50 from Amazon and Kobo), and culled some quotes. Here they are:
BANKRUPT Means “broken bench”: “Money lenders in Northern Italy once did business in open areas, or big open rooms, with each lender working from his own bench or table. If he went ‘broke’, the piece of furniture was literally broken to signify that he wasn't in business anymore.” (straightdope.com)
BEST MAN Groom’s bodyguard. “In feudal times, it was commonplace for rival Lords to storm a wedding and steal the bride for political reasons.” (scriptonitedaily.com I thought the best man was there to protect the groom from the kidnapped bride’s family… See many ancient traditions of marriage by capture, and strange items of “wedding theatre” based on them.)
BIKINI "The idea was that their impact was like a nuclear explosion. As indeed it was, at a time when swimsuits were modest and often had little skirtlets." (RN)
BISTRO “The word ‘bistro’ (or ‘bistrot, as it is sometimes rendered) comes from the Russian word ‘bistro’, meaning ‘quickly’. The story goes that, when Paris filled up with Russian émigrés after the 1917 revolution, they used to demand food ‘bistro, bistro!’, which is how these early fast-food joints came to be so named.” (SL)
BLACKGUARD Merriam-Webster says: “From black + guard. The term originally referred to the lowest kitchen servants of a court or of a nobleman's Household. They had charge of pots and pans and other kitchen utensils, and rode in wagons conveying these during journeys from one residence to another. Being dirtied by this task, they were jocularly called the ‘black guard’.” The Free Dictionary agrees: “the lowest menials in court, camp followers, vagabonds”. The Urban Dictionary suggests it’s from shoeshine boys.
BROWNIE POINTS “Said to originate with a Pullman Car captain called Brown who awarded merits and demerits to his crew”, friend A writes. “Or brown-nose”, says friend B. Friend A supplied the following: “In the 1930s, Curtis published magazines including the Saturday Evening Post and the Ladies Home Journal. They were distributed door-to-door by youths, primarily boys, who received a small commission. If they met sales targets, they could also receive green and brown vouchers to be redeemed against goods from the company's catalogue. These vouchers were known as ‘greenies’ and ‘brownies’; five greenies equalled one brownie.” Ingenious, but surely the points were earned by trainee Girl Guides (called Brownies after the helpful elves of fairy stories)? (Wikipedia gives all these and more. NGram shows a sharp rise in popularity from 1960.)
CINDERELLA’S SLIPPER “The slipper probably was not glass at all: the mistake was made through the similar French words verre, glass, and vair, fur,” said Simon Hoggart in The Guardian, December 7 1999. But the consensus among folklorists is that it's, well, folklore… As the French folklorist Paul Delarue pointed out in a 1951 essay, ‘one can also find [glass shoes in Cinderella stories] in other countries where there is no homonym which permits the confusion’.”)
DEED POLL “Poll is an old English word used to describe a legal document that had its edges cut (polled) so they were straight. This was done to visually distinguish between a deed signed by one person (a polled deed - hence the term Deed Poll) and a deed signed by more than one person (an indenture), which had an edge indented or serrated. Interestingly, indentures were originally written twice (side by side) on one piece of parchment, which was then torn down the middle and each half given to each party. The impossibility of matching the tear was a guard against forgery.” (UK Deed Poll Service website)
DUDE “It seems almost certain that ‘dude’ derived from ‘doodle’, as in ‘Yankee Doodle Dandy’. ... For some reason, early in 1883, this inspired someone to call foppish young men of New York City ‘doods’, with the alternate spelling ‘dudes’ soon becoming the norm.” (Allan Metcalf)
FIASCO “English speakers picked up ‘fiasco’ from the French, who adopted it from the Italian phrase ‘fare fiasco’ - ‘to make a bottle’… One guess is that when a Venetian glassblower discovered a flaw developing in a beautiful piece he was working on, he would turn it into an ordinary bottle to avoid having to destroy the object.” (Merriam-Webster) The Free Dictionary says: French, from Italian fare fiasco, to make a bottle, fail, from fiasco, bottle (perhaps translation of French bouteille, bottle, error, used by the French for linguistic errors committed by Italian actors on the 18th century French stage).
FILER A L’ANGLAISE In French, “take French leave” is “leave like the English”. But it’s really from “angler”, or “fish”: “L’expression proviendrait de l’ancien verbe ‘anglaiser’, pour ‘voler’. Par la suite, on aurait utilisé ‘filer à l’anglaise’ pour désigner la façon discrète dont part un voleur qui vient de faire son coup. Par analogie, on a aussi vu apparaître l’expression ‘partir comme un voleur’.” (Oh those French and their puns! Angler (fish) sounds like Anglais (English).)
FINE TOOTHCOMB “I have heard it said that the term ‘comb’ once included implements that did not have teeth, so ‘tooth comb’ may have been a necessary distinguishing epithet”.
FOGGY DEW fog is a kind of grass that “grows in marshes and bogs where the atmosphere would be damp and misty, and this would represent maidenhead, and the dew would imply virginity or chastity”. (“There seems no end to what can be interpreted from the lines of folksongs," says Folksongs of Britain and Ireland.)
HILL OF BEANS “a planting method whereby four or five beans are put in a mound.” (answers.com)
I DON’T GIVE A D**** “An obsolete Indian copper coin of very little value called a dam,” suggests Sunanda K. Datta-Ray in the International Herald Tribune, 15 Mar 2000. (So “I don’t give a tuppenny dam” would make no sense. And some people say “tinker’s cuss”. It was a damn, dammit!)
JOHN O’GROATS Jan de Groot “He charged 4d a trip apparently, and they will tell you in these parts that that sum became known ever after as a groat, but alas it is a pathetic fiction. It is more probable that Groot was named Groat after the money rather than it for he.” (Bill Bryson’s Notes from a Small Island)
MIDSUMMER “Maybe it has the same etymological origin as the word midwife – meaning ‘with’?” (The Guardian, 7 June 2011)
SINCERE Merriam-Webster says: “The allusion is to the Roman practice of concealing flaws in pottery with wax, or to honey from which all the wax has been extracted.” (Make up your mind!) Wikipedia says: “The Oxford English Dictionary and most scholars state that sincerity from sincere is derived from the Latin sincerus meaning clean, pure, sound (1525–35). Sincerus may have once meant "one growth" (not mixed), from sin- (one) and crescere (to grow).”
TAWDRY From St Audrey: “There used to be a huge fair in her honour this day in Ely where bits of tatty lace were sold to pilgrims.” (Rev Richard Coles) “Necklaces of silk and lace were sold, often of very inferior quality.” (el.anglican.org) “A lot of cheap bobbin lace was sold.” (buttercupminiatures.co.uk)
WALLY Why does it mean “a fool”? “Originally pronounced as in valley in place of origin Glasgow, before being distorted by Londoners especially who believed the Scots were actually saying the male name 'Wally', it relates to a tenement stairway, a 'close', that was titled 'a wally close' pronounced as in valley, and where the more well-off families lived, and who kept their children from playing with the 'roughs' with the consequence that lack of 'playing out' led to less well co-ordinated (less socially skilled as well, therefore) people, 'wallies' (as in valleys).” (onlineslangdictionary.com) (The longer and more circumstantial the explanation, the less I believe it.)
“Folk etymology always leaps for acronyms.” (RN)
More here, and links to the rest.