Antonyms for the word "more jam-packed" would include "spacious," "empty," and "uncluttered." These words describe the opposite of a crowded and chaotic environment that is often associated with a "jam-packed" space. "Spacious" implies a large and open layout with plenty of room to move around, while "empty" suggests a lack of occupants or objects in the space. "Uncluttered" means free from any unnecessary items or mess, resulting in a clean and organized environment. Using these antonyms in place of "more jam-packed" can provide a more positive and peaceful description of a space that is not overcrowded.