Dep comes from Vietnamese everyday speech, where the word is used to tell someone to clear off or drop a subject. Online, the clipped form has travelled as a reaction sound in short videos and meme edits, where its meaning is carried more by tone and timing than by translation. Because it is only one word, it is easy to drop into a cut, a duet or a reply, and it keeps working across languages as a universal sign of impatience. Its popularity rests on that brevity, not on a single viral clip.