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, 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
USA, 1957—the rhythm method of birth control, as permitted by the Roman Catholic Church—with allusion to the unpredictable efficacy of this contraceptive method: from ‘Vatican’, denoting the authority of the Roman Catholic Church, and ‘Russian roulette’
USA, 1917—originally and chiefly military slang—an inspection of the penis for venereal disease or other infection—the image is of the penis as an additional, but shorter, limb
‘serious trouble’—USA, 1866—from the image of taking off one’s shirt before getting into a fight, and from ‘hell’ in the sense of ‘a severe reprimand’, as in ‘to give someone hell’