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)
prostitution—1889 as ‘the most ancient profession in the world’ in On the City Wall, by Rudyard Kipling—was used earlier, with positive connotations, of various professions, especially agriculture
in a state of nudity—1732 as ‘in one’s birthday clothes’—refers to the naked condition in which a person is born—here, ‘birthday’ means ‘the day on which a person was born’
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
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)
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