Not Safe For Work. Used to describe Internet content generally inappropriate for the typical workplace, i.e., would not be acceptable in the presence of your boss and colleagues (as opposed to SFW, Safe For Work).

NSFW is an abbreviation for words like Not Safe For Wife, Not Suitable For Work, but mostly accepted as Not Safe For Work.

It is an internet slang that is often used to describe online posts that are mainly associated with heavy nudity, sexual, heavy profanity and other things that could often link with pornography. Most of the time, NSFW is used for a fandom of some sort when people want to discuss and share the sexual and porno side of the fandom.

Now Show Friends and Workmates - a suggestion that the viewer draw the attention of friends and/or workmates to their computer screen before following a link or viewing further content. This indicates that the following content is interesting, informative or inspiring, usually in such a way that it will get the viewer promoted and increase workplace productivity.

No, seriously, this shit will get you fired.

Not Safe For Work, used to refer to documents that would probably get you fired if you were looking at them on worktime. Usually R rated or higher.

Acronym: Not Suitable For Work.

Used when posting a link to a site of dubious merit which could cause embarrassment/P45 if linked to while using the Internet at work

An abbreviation meaning "Not Safe For Work," used as a warning tag for overpaid workers who can browse the internet at work just as long as it doesn't involve swearing or nudity.