Is it ensure, insure, or assure?
1929, adjective and noun, from French nudiste or formed in English from nude (adj.) + -ist; also see nudism.
1929, from French nudisme (see nude + -ism). Nudist "one who practices nudism" appeared at the same time.
Made in Germany, imported to France, is the cult of Nudism, a mulligan stew of vegetarianism, physical culture and pagan worship. ["Time," July 1, 1929]