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Not safe for work (NSFW) is Internet slang or shorthand used to mark links to content, videos, or website pages the viewer may not wish to be seen viewing in a public, formal, or controlled environment. The marked content may contain graphic violence, pornography, profanity, nudity, slurs, or other potentially disturbing subject matter. Environments that may be problematic include workplaces, schools, and family settings. NSFW has particular relevance for people trying to make personal use of the Internet at workplaces or schools that have policies prohibiting access to sexual and graphic subject matter. Conversely, safe for work (SFW) is used for links that do not contain such material, especially where the title might otherwise lead people to think that the content is NSFW.
The similar expression not safe for life (NSFL) is also used, referring to content which is so nauseating or disturbing that it might be emotionally scarring to view. Links marked NSFL may contain fetish pornography, gore, or murder.
Some websites, such as Reddit and OnlyFans, give users the option to designate their content as NSFW in order to warn others of its inappropriate nature.