A metallurgist is a person whose work is metallurgy: the scientific study of metals and their uses. They look at how we get metals from rock, how we melt and mix them, and how we make them right for a job — a plane that must stay light and strong, a wire that must not snap, steel that must not rust too fast. They may work in a lab, a factory, or a mining company. The -ist tells you this word names the person, not the subject. It is a formal job-and-science word.