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)
USA, 1888—an enigmatic, mysterious smile, reminiscent of that represented in the Mona Lisa, a portrait of Monna Lisa del Giocondo, painted by Leonardo da Vinci
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)
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’
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
USA, 1826, as ‘to flog somebody like seven bells’—to give a severe beating to somebody—‘seven’ is perhaps simply an arbitrary intensifier—cf. phrases such as ‘like seven bells half-struck’ (‘with as much speed as possible’) and ‘to blow seven bells’ (‘to blow a violent gale’)