Shoot, I don't know or Shit, I don't know.
HISTORY: A young man named Bob who was working for the Pacific Missile Test Center at Point Mugu Naval Air Station in the 1970s, and was a student in the engineering development program "SED", class #15, was presented with a Navy document loaded with acronyms and his boss asked him what he thought of the proposal. His reply was the acronym SIDK. And it spread from the Navy lingo outward. And that's the truth!
When someone throws you a series of acronyms you don't understand, this is the one you use in reply, sidk.