The antonyms for "popped in" include "left," "exited," "departed," "withdrew," "disappeared," "vanished," "evaporated," "fled," "retired," and "returned." The phrase "popped in" implies a brief and sudden visit, and the opposite actions involve leaving or exiting in a more deliberate or gradual manner. For example, someone who "pops in" might just drop by for a quick hello without a plan or announcement, but someone who "left" or "withdrew" would likely have stated their intention beforehand or taken a more purposeful exit. Understanding these antonyms helps us communicate nuances of time, urgency, and intention in our interactions with others.