Australia, 1950—a traffic warden in the state of New South Wales—‘brown’ probably refers to the colour of those traffic wardens’ uniform—‘bomber’ may refer to the fact that many of those traffic wardens were originally war veterans; or perhaps to the Australian-English use of the noun ‘bomb’ for an old car
USA—‘squillion’ (1879): an extremely large but unspecified number, quantity or amount; arbitrary and humorous alteration of ‘million’, ‘billion’, etc.—‘squillionaire’ (1895): a person who has an extremely large but unspecified amount of money
UK, 1899—derogatory—a foreigner; a personification of foreign people—‘Johnny’ is used with modifying word to designate a person of the type, group, profession, etc., specified
military slang, 1944—a medal awarded to all members of a force—especially the 1939-1945 Star, awarded to British service personnel who took part in WWII—refers to the ubiquitousness of Spam as a foodstuff
UK, 1975—an upper-class and fashionable, but conventional, young woman in London—blend of ‘Sloane Square’, the name of a square located in an affluent area of London, and ‘Lone Ranger’, the name of a well-known hero of western stories and films
UK, 1920—an Arab man—‘Johnny’, a pet form of ‘John’, is used, with modifying word, to designate a person, especially a man, of the type, group, profession, etc., specified
UK, 1912—humorous: a Jewish person—refers to the Crossing of the Red Sea, as recounted in the Book of Exodus—coined on various occasions by different persons, independently from each other
a standard or device for the measurement of foolishness or folly—coined by the British author Sydney Smith (1771-1845) in ‘Second Letter to Archdeacon Singleton, Being the Third of the Cathedral Letters’ (London, 1838)