What does it mean to cause something to be filled with a specific substance?

The term that best describes the act of causing something to be filled with a specific substance is "infuse." When you infuse something, you are introducing a substance into another, enhancing it or altering its characteristics by permeating it with that substance. This is often seen in contexts such as flavoring food or beverages, where an ingredient is steeped to impart its qualities.

In contrast, "instill" refers more to teaching or introducing an idea or feeling gradually, rather than filling something physically. "Incorporate" indicates the action of combining or integrating different elements into a whole, which may not necessarily involve filling something with a substance. "Embed" typically means to fix or implant something firmly within a surrounding mass, which suggests a physical placement but doesn’t inherently imply the act of filling with a liquid or another substance. Thus, "infuse" is the most accurate choice for describing the action of filling something with a specific substance.