NSFW means "not safe for work." Alyssa Powell/Insider NSFW is an internet acronym that means "not safe for work." NSFW often serves as a content warning, urging the viewer to use discretion or avoid the post or image when they are in a professional or public setting. On the more extreme end, content may carry a NSFL (not safe for life) tag to warn about potentially disturbing content. Visit Insider's Tech Reference library for more stories. If you've spent any time on social media or in forums that occasionally feature edgy or explicit content, you've likely encountered the acronym, NSFW,