Densifying, which means to make something more dense or compact, has several antonyms that refer to making something less dense or sparse. Some of these antonyms include: rarefying, scattering, dissipating, thinning, reducing, sparsing, and diffusing. Rarefying refers to making something less dense, while scattering refers to separating something into small pieces or particles. Dissipating means to spread or disperse something, often resulting in reduced density. Thinning refers to making something less thick, and reducing refers to cutting back on something or making it smaller in amount or density. Sparsing and diffusing refer to spreading out or dispersing something, leading to reduced density or concentration.