Which word refers to a product that is unoriginal and derived from something else?

The term that describes a product that is unoriginal and derived from something else is "derivative." In the context of creative works, a derivative is typically a piece that borrows heavily from previous ideas, concepts, or content, rather than presenting a fresh or unique creation. This can apply to literature, music, art, and numerous other fields where innovation stems from existing works. Derivative works often lack the originality that characterizes truly inventive creations, which is why the word is frequently used in discussions around intellectual property and creative industries.

The other options relate to different concepts. "Dexterity" typically refers to skillfulness or agility in movement, especially involving the hands. "Detriment" indicates something that causes harm or damage, while "dilutive" refers to a reduction in value or significance, often in the context of investment or shares. None of these terms accurately convey the idea of being unoriginal or derived from existing material, making "derivative" the most appropriate choice.