Leaden describes something that feels as heavy, dull, or slow as lead, the dense gray metal. When your legs feel leaden after running sprints in gym class, they seem to weigh a ton and barely want to move. A leaden sky on a dreary winter day looks flat, gray, and oppressive, without a hint of blue or brightness.

The word often captures a feeling of heaviness that goes beyond just physical weight. A speech might be leaden if it drags on in a monotonous voice, making everyone in the audience feel tired and stuck. A book with leaden prose reads slowly and laboriously, its sentences clunky and hard to push through.

Lead itself is remarkably dense: a small cube of lead feels shockingly heavy when you pick it up, much heavier than the same size cube of wood or plastic. That physical property gives us this useful word for describing anything that seems weighted down, whether it's your exhausted muscles, a gloomy atmosphere, or writing that plods along without energy or life.