1691—to expose the flaws in something such as a law, a policy, an argument or a belief—these flaws are likened to holes large enough to drive a coach and horses through them
a person or thing, initially ugly or unpromising, that changes into something beautiful or admirable—New Zealand, 1848—from Hans Christian Andersen’s story about a supposed ugly duckling that turns out to be a swan
two different people or things are totally incompatible—1901—alludes to “East is East and West is West, and never the twain shall meet” in Ballad of East and West (1892), by Rudyard Kipling
1809—U.S. nautical, obsolete: the two-fathom mark on a sounding-line—Samuel Langhorne Clemens chose it as his pen-name in 1863, but a pilot named Isaiah Sellers had first used it as his pen-name
also ‘mustang court’ and ‘kangaroo inquest’—USA, 1840—a mock court that disregards or parodies existing principles of law; any tribunal in which judgment is rendered arbitrarily or unfairly
USA, 1792—to say to a person the things that they want to hear—allegedly from the story of a white man and an Indian who went hunting together, and killed a turkey and a buzzard
irresponsible or unfounded optimism—1857, apparently coined by Charles Dickens—refers to Wilkins Micawber, a character in Dickens’s novel David Copperfield (1850)
the Jerusalem artichoke—UK, 1968—blend of ‘fart’ and ‘artichoke’ in ‘Jerusalem artichoke’—refers to the flatulence caused by eating Jerusalem artichokes