DSI

"DSI" = "Do Something Intelligent"

This refers to a low level double that is card showing or cooperative. A player will employ this double then he or she wants to compete but has no clear action. It says to partner, "This isn't meant as penalty but from my side I am not sure of the best place to be or the best action to take. I don't have a trump stack (or no trump), so you decide."

Source:  http://larryco.com/BridgeArticles/ArticleDetails.aspx?articleID=553  (Low Level Doubles)