na·tur·ism
noun/ˈneɪtʃərɪzəm/
/ˈneɪtʃərɪzəm/
(especially British English) (also nudism British and North American English)
[uncountable]- the practice of not wearing any clothes because you believe this is more natural and healthy
裸体主义（认为裸体更自然更有益健康）