Emily Dickinson Lexicon

CLUMP, n. [G. klump; D. klomp; Sw. klimp; Dan. klump, a lump; W. clamp. It is lump with a prefix. It coincides with plump, and L. plumbum, lead; as the D. lood, G. loth, Dan. lod, Eng. lead, coincide with clod. It signifies a mass or collection. If m is the final radical, see Class Lm, No. 1, 4, 5, 9. L. glomus.]

1. A thick, short piece of wood, or other solid substance; a shapeless mass. Hence clumper, a clot or clod.
2. A cluster of trees or shrubs; formerly written plump. In some parts of England, it is an adjective signifying lazy, unhandy. – Bailey.