Naturists find going without clothing both enjoyable and relaxing.Nudism, or naturism, is the practice of going nude or unclothed in social and usually mixed gender groups, specifically in cultures where this is not the norm. It sometimes occurs furtively in secluded places in countries where appearing naked in public is illegal, but enjoys widespread acceptance in other areas of the world. Those who practice nudism are called nudists or naturists. Some people believe that being naked with other people is necessarily always sexual, or that nudism is morally wrong or pornographic. Naturists generally reject these views.

Typical activities are sunbathing and sports, but some nudists prefer also to be nude while working etc., whenever the temperature and the social situation allows it (including when one is alone).

Naturism (pronounced "nature" + "ism") should not be confused with naturalism, the study of nature.

Nudists believe that the human body is nothing to be ashamed of, being something that we all possess and ought to cherish. Consequently, nudists participate in various social activities in the nude.

Although the terms are used interchangeably in this article, some would draw a distinction between the terms nudism and naturism. In this view a nudist is one who sometimes chooses to go without clothes. A naturist is one who embraces a philosophy that includes more than occasional nudity, often environmentalism, vegetarianism or simply more of a closeness to nature. Others would argue that the term naturism implies snobbery, and there is no distinction. A visit to a nude beach may entitle someone to be called a nudist, but does not make one a naturist. Changing and showering in a locker room probably does not qualify for either. Doing housework in the nude might. Many nudists do so casually at home.

A common thought of nudists is being "always naked under my clothes". An alternate usage of these terms held by some North Americans is: nudist=nude indoors, naturist=nude outdoors. The nudist or naturist label is really a state of mind of the practitioner, instead of a strictly defined classification imposed by others.

Some nudist organizations do not allow people with body piercings on their premises. (Presumably this rule refers to the foreign objects in the piercings, not to the piercings themselves.) Most, however, accept people of all sizes, shapes and types including those with surgical scars, tattoos or interestingly trimmed (or absence of) hair.

Nudism is not equivalent to exhibitionism. It is people who enjoy being nude and who are not primarily interested in seeing others naked (strictly, voyeurism) or being seen naked by others. That being said, all kinds of people are attracted to the movement, for all kinds of reasons. Many naturists are convinced that increased exposure to the natural environment, made easier through nudity, can result in numerous health benefits. Sunlight has been shown to be beneficial in some skin conditions, and is required by the body to make vitamin D. However, with the increased awareness of skin cancer, wearing of sunblock/sun protection lotions is now part of the nudist culture and is one of their frequently discussed topics. Whereas nudist parents don't require their children to put on clothes before going outside at a nudist club or beach, most do require them to put on sunscreen lotion. Overall, naturists often claim that they are more relaxed and in a better state of mind when they shed their clothes.

Being around like-minded people can make interpersonal interactions, such as meeting new friends, easier and many nudist organizations are really just social clubs. Indeed, some of these clubs have stricter entrance requirements than some traditional up-scale 'country clubs' requiring references, a sponsoring member, a trial membership, committee approval, and, due to fears about sex offenders, criminal background checks. At the other end of the spectrum is 'unorganized' naturism in which there is nothing to join, no one to pay, and only civil, common and criminal law to serve as rules of etiquette. Many people get their first exposure to the naturist movement through this kind of informal nudism (e.g. a clothing optional beach, a friend's place in the woods, a party on the shore; skinny dipping).

Nudists will wear clothes if the weather demands it. Naturists are generally accepting people, the general idea being simply doing things nude that one would normally do clothed. Manners are important. The most essential thing to bring to any nudist site is a towel to sit on. It is very poor etiquette to sit on a chair, bench, or anything else where others might sit on without your towel. Also, never sit on someone else's towel.

Other rules may include a prohibition on cameras (including cell phone cameras), pets, loud music, etc. Always check the specific rules before visiting a new nudist site, as policies vary. Some nudist resorts, clubs, or beaches require full nudity at all times (with possible exceptions). Most have this policy only for the swimming pool, sauna, Jacuzzi, hot tub bath, etc., with clothing optional elsewhere. Recently, to avoid any possible litigation, some privately owned resorts and clubs in the USA forbid bringing any minor children from other families without written permission in advance. A few even exclude children of divorced parents without the written consent of the other ex-spouse (unless they can prove full custody). Of course, this does not apply to public beaches.

Strong nudist movements exist in Germany (called FKK or Freikörperkultur - Free Body Culture), France and the Netherlands, and smaller such organizations exist in many other nations. Social nudity is practiced in many cultures, especially in the context of social bathing, sometimes with mixed sexes.