Antonyms for the word "most spread out" include "concentrated," "compact," "dense," and "crowded." These words indicate a state of being gathered closely together, rather than being widely dispersed. Other opposite words could be "centralized," "clustered," "grouped," or "tightly packed." These antonyms may describe objects or people, and could be used in a variety of contexts such as describing a city's population or the organization of data. In contrast to "most spread out," these words often suggest a sense of efficiency, organization, or a desirable level of proximity.