Naturism is the belief, and the way of life, of people who like to go without clothes because they think the naked body is natural, and that this is healthy and honest — not something to hide, and not something that is only about sex. They may go to special beaches or camps where nobody wears clothes. Another English word for this is nudism; naturism is the one many people prefer when they want to sound respectful and to stress nature and the body, not just being naked. It is not a word you use in everyday small talk unless the topic comes up. It is also easy to mix with naturalism, which is a completely different word about art, books, or a view of the world. Naturism here is about not wearing clothes.

天體主義。台灣也說裸體運動；去的地方叫天體營。不是「自然主義」（那是 naturalism）。