A smith is someone whose job involves making things out of metal. Visit a historically accurate colonial village and you might see a smith making tools or nails by hand.
Smith or smithy is shorthand for blacksmith, an artisan who hammers tools and other items out of hot iron or steel. You can also use smith for a variety of other workers, especially if they make things, like a bladesmith or a coppersmith, or work with their hands, like a locksmith or a gunsmith. You can even call a writer a smith — or "wordsmith." The Proto-Indo-European root of this word means "to cut" or "work with a sharp instrument."