Which term means to make something thinner or less dense?

The term that means to make something thinner or less dense is "rarefy." This word is often used in scientific contexts, particularly in physics and chemistry, where it refers to the process of reducing the density of a substance, such as gases. When a gas is rarefied, its molecules are spread out, leading to a decrease in density. This can happen through processes like heating, which causes the gas to expand, or decreasing pressure, allowing the molecules to move farther apart.

The other terms do not relate to making something thinner or less dense. "Raucous" describes a loud and chaotic noise, "rabid" refers to having extreme enthusiasm or being infected with rabies, and "profane" relates to disrespect or irreverence toward sacred things. Each of these words has distinct meanings unrelated to the concept of density or thinning.