Not safe for work
Not safe for work (often shortened to the acronym NSFW) is an Internet slang or shorthand used to mark URLs and hyperlinks which link to videos or websites pages containing nudity, intense sexuality, profanity, violence, and/or other potentially disturbing subject matter, which the viewer may not wish to be seen looking at in a public or formal environment, including a workplace or school. NSFW has particular relevance for people trying to make personal use of the Internet at workplaces or schools which have policies prohibiting access to sexual and graphic subject matter.
The similar expression not safe for life (shortened to 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, and/or lethal violence.