UK, 1914—snobbish or supercilious—refers perhaps to ‘toff’, denoting a fashionable upper-class person—the image is perhaps of someone who, considering themself superior, keeps their nose high in contempt for the lower classes—cf. the form ‘toffy-nosed’ (1919)
1727—a labourer of the lowest kind—refers to the enslavement of the Gibeonites by the Israelites in the Book of Joshua, 9:21-27, as it occurs in the King James Bible (1611)
USA, 1918—a mechanic—since the 17th century, ‘monkey’ has been used (frequently with modifying word indicating the occupation concerned) to denote a person engaged in a trade or profession
UK, WWII, army slang—‘spud-bashing’ (noun): potato-peeling; ‘spud-bash’ (verb): to peel potatoes; ‘spud-basher’ (noun): one who peels potatoes—those words have also been used with reference to potato-digging
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, 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
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
Australia—meaning: (as a verb) to rest or spend time in an aimless, idle way; (as a noun) an instance or period of resting—origin: Army slang, Second World War, from the notion of lying on one’s back