Best definition
You Understand Me?
A USMC drill instructor’s favorite phrase to add onto every single sentence. It is extremely annoying. Drill Instructors must be

taught to say this to recruits to annoy them because ALL OF THEM do it.

Drill Instructor: “We are stepping off to chow in two minutes, you understand me? Don’t be the one that isn’t done making their rack by then, you understand me? I will slay you if you are fucked up in any way once you walk out that hatch, you understand me?!”