The antonyms for the word "more ferrous" are "less ferrous" or "non-ferrous". Ferrous refers to the presence of iron, and non-ferrous metals are those that do not contain iron, such as copper, aluminum, or zinc. These non-ferrous metals are often used for their resistance to corrosion, lightweight, and ability to conduct electricity. In contrast, ferrous metals like steel, iron, and cast iron are known for their strength, durability, and magnetic properties. Understanding the difference between ferrous and non-ferrous metals is crucial for selecting the right material for a specific application, whether it be in construction, manufacturing, or electronics.