Variation of the well known acronym "JK." OJK simply means Obviously Just Kidding. It is often used when the speaker doesn't want to offend the listener.
Margie: Hey my bff jill, do you wanna hang out?
Jill: Umm no, I would die...OJK! Of course Id want to!
Margie: This is going to be so much fun!
Jill: Umm no, I would die...OJK! Of course Id want to!
Margie: This is going to be so much fun!
by Louis K. Lane April 16, 2009