1531, a legal term, "unsupported, not formally attested," from L.
nudus "naked, bare" (see
naked). General sense of "mere, plain, simple" attested from 1551. In ref. to the human body, meaning "unclothed" is an artistic euphemism for
naked, dating from 1611 (implied in
nudity).
Nudism is a 1929 borrowing from Fr.
nudisme; 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]
Nudie "a nude show" is from 1935.