NJ
No joke
NJ is an acronym typically seen online or in text messages that means "no joke." The acronym is the opposite of JK.
NJ is used when you want to emphasize the seriousness of a comment, even though it may seem ridiculous or unbelievable. The acronym is similar to NK.
Example
NJ, he really got the senior editor position?

NJ is all business
An acronym used as a compliment, commonly in multiplayer gaming; similar to saying, "Nice work."