Definitions for "Rootbound"
A condition which exists when a potted plant has outgrown its container. The roots become entangled and matted together, and the growth of the plant becomes stunted. When repotting, loosen the roots on the outer edges of the root ball, to induce them to once again grow outward.
When plants out-grow their containers and their root-balls don't have enough space left for further growth.
When a plants roots become tangled, matted, and grow in circles. Always untangle rootbound plants when replanting them in a larger container or in the ground.