UK, 1830—‘Jenny Darby’, ‘Johnny Darm’, and variants, were originally opprobrious names for any member of the new Metropolitan Police introduced in 1829 by Robert Peel—alterations of ‘gendarme’, with full or partial folk-etymological remodelling variously after the female forename ‘Jenny’, the male forename ‘Johnny’, and the surname ‘Darby’
Ireland, 1809—the Wednesday before Easter—refers to the day on which Judas Iscariot formed the intent to betray Jesus—‘spy’ denotes ‘one who spies upon, or watches, a person or persons secretly’, because, from Wednesday onwards, Judas Iscariot secretly sought an opportunity to deliver Jesus to the Jewish authorities
Northern England—a filled or open sandwich—originally (1827): a slice of bread spread with butter—composed of ‘butt-’, from the noun ‘butter’, and the suffix ‘-y’, forming diminutive nouns
USA, 1812—UK, 1818—the name of a character proverbially said to have been so great a liar that he was expelled from Hell—hence, frequently in ‘a bigger liar than Tom Pepper’, and variants: an outrageous liar
Lancashire, England, 1833—a faggot, a meatball, “a compound of onions, flour, and small pieces of pork” (The Liverpool Echo, 20 August 1880)—probably one of the common dishes humorously named after daintier items of food
UK, 1929—a drink of alcohol—especially used of an initial drink taken by someone (e.g. a young person) who is particularly susceptible to the effects of alcohol
UK and Ireland—with reference to the fact that Horatio Nelson was blinded in one eye—(1922) ‘until/when Nelson gets his eye back’ is used of a very long time in the future—(1933) the metaphor of Nelson getting his eye back is used of a very small chance of success
UK, 1892—very rarely—refers to the fact that Preston Guilds are held only once every twenty years—Preston is the administrative centre of Lancashire, a county of north-western England, on the Irish Sea