UK, 1894—a love-relationship in which one member of a married couple is involved with a third party—loan translation from French ‘triangle éternel’, coined by Alexandre Dumas fils in L’Homme-Femme (1872), a pamphlet about a wronged husband’s right to take the life of his adulterous wife
UK, 1942—a weekly hour of religious instruction provided by chaplains to British-Army units—‘padre’ (literally ‘father’) is colloquially used to designate and address a male chaplain in the armed forces
UK, 1922—used in negative constructions with a following noun to mean ‘a single ——’, ‘any ——’; the nouns most commonly used in those constructions are ‘notice’ and ‘difference’
a profession which has long been established or which is regarded as having similarities with prostitution—also sometimes used jocularly—alludes to ‘the oldest profession in the world’ (i.e., prostitution)
a man’s habit of sexual promiscuity or infidelity—refers to the zipper on the flies of a pair of trousers—USA, 1982, originally used of Members of Congress in Washington, D.C., and recorded by gossip columnist Diana McLellan
UK, 1803, as an adjective—UK, 1842, as a noun—in reference to the action or practice of attacking, or acting against, someone in a treacherous or underhand manner
Ireland, 1914—the action or practice of attacking, or acting against, someone in a candid or open manner, as opposed to deceptively or duplicitously—coined after ‘backstabbing’ (i.e., the action or practice of attacking, or acting against, someone in a treacherous or underhand manner)
USA, 1995—a freelance videographer or photographer, characterised as being extremely aggressive in pursuing celebrities to video or photograph them—a blend of the nouns ‘stalker’ and ‘paparazzo’
chiefly UK politics—a culture characterised by influential networks of close friends—from ‘chum’ (a close friend) and ‘‑ocracy’ (forming nouns designating forms of government or groups who exercise political or social power)