The term "fleshes out" refers to adding substance and detail to something. Antonyms that one can use instead of fleshes out include "simplifies," "abbreviates," "reduces," "condenses," "trims," "cuts," and "shortens." These words convey a sense of taking away from something rather than adding to it. While fleshes out emphasize the importance of adding layers, details, and complexity, its antonyms suggest the opposite. This can be useful in situations where one needs to convey information more succinctly or simplify a concept so that it is easier to understand.