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
notoriously used of the Beatles by John Lennon in an interview published in the Evening Standard (London, England) of 4 March 1966—but had been used earlier, for example in 1927 of Charlie Chaplin
1923: a small garment worn to cover the genitals—hence (1926): anything intended to conceal something regarded as shameful or indecent—from French ‘cache-sexe’, from ‘cacher’ (to hide) and ‘sexe’ (sex, genitals)
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’
an early account of a forced choice from a number of horses, associated with William Hobson (died 1581), a London haberdasher—itself adapted from earlier accounts, in which the main protagonist remained unnamed
UK, 1914: an apparent ability to sense or intuit the presence of nearby spiders—USA, 1963, in reference to Spider-Man: a supernatural ability or power to perceive things beyond the normal range of human senses
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)
New Zealand (1890) & Australia (1891)—to terrify somebody—probably modelled on the earlier phrase ‘to knock seven bells out of somebody’ (‘to give a severe beating to somebody’)