Also called a dutch tilt or canted angle, the technique simply rotates the camera on its lens axis so vertical lines lean. The name is a corruption of Deutsch — the device was a signature of German Expressionist cinema in the 1920s, where distorted framing externalised psychological states.
It works because the brain expects horizons to be level and uses them for orientation. Breaking that expectation produces genuine low-level discomfort, which is why the shot recurs in horror, thrillers, and depictions of intoxication, madness, or vertigo. The degree matters: a subtle few degrees creates unease the viewer cannot quite name, while a hard forty-five is overt stylisation.
It is easy to overuse. Applied without motivation it reads as an affectation, and applied constantly it stops registering at all — the viewer simply recalibrates. The strongest use is sparing and pointed, marking the moment a scene turns, ideally alongside something else changing in the frame.