The term 'MAKES HARD' can be solved by the word 'STEELS', which is a six-letter word. Steel is an alloy of iron and carbon, and is one of the most commonly used metals in the world. It is known for its strength and durability, making it a popular choice for construction and manufacturing. Steel is also used to make tools and weapons, as well as for decorative purposes. Steel is often treated with heat or chemicals to make it harder and more resistant to wear and tear.