A fork of Rural Dictionary
Acronym for Scotty Doesn't Know. Can be used in place of I don't know (see idk). Especially effective for people name Scotty, or from Scotland, or the chief engineer and third-in-command on the starship Enterprise.
Guy: Hey, who used my toothbrush? Dude: SDK.
Acronym for "laughing out loud but not really". Because how many times are you actually laughing out loud when you type "lol"? Exactly.
Guy: ...That's what she said! Dude: LOLBNR