A lot vs. Alot: 9 Grammatical Pitfalls
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]
the practice of going without clothes, generally for reasons of health or comfort. Nudism is a social practice in which the sexes interact freely but commonly without engaging in sexual activities