An acronym for "Cluster Fuck Disaster", a phrase that describes a hopelessly disordered situation. It achieves the most utility when used by engineers in an academic or industrial setting, as it shares an identical acronym with Computational Fluid Dynamics, a popular branch of fluid mechanics.
Student: "Dude, let me copy your homework, I have no idea what's going on with these equations I copied from the other guy, its totally CFD."
Engineer: "Did you go to that meeting today? Nobody knew what was going on. CFD."