nudist

1530s, a legal term, "unsupported, not formally attested," from Latin nudus "naked, bare, unclothed, stripped," from PIE root *nogw- "naked" (see naked). General sense of "mere, plain, simple" is attested from 1550s. In reference to the human body, "unclothed, undraped," it is an artistic euphemism for naked, dating from 1610s (implied in nudity) but not in common use in this sense until mid-19c.

word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.

Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.

"The cult and practice of going unclothed" [OED], 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]