1. a person or thing that clumps; something that forms or moves in clumps or heavy clusters
Usage: informal; often used in agriculture or gardening contexts
2. a heavy, clumsy person or animal
Usage: informal; sometimes derogatory

Examples

• The soil clumper broke up the hard earth into manageable pieces.
• He walked across the floor like a clumper, making noise with every step.
• The clumper of dirt fell apart when we watered the garden.
• That clumper knocked over three glasses at dinner.
• The machine acts as a clumper, gathering loose particles together.