clump

noun

• 1a compacted mass or lump of something:clumps of earth
• a small, compact group of people:they sat on the wall in clumps of two and three
• a small group of trees or plants growing closely together:a clump of ferns
• Physiology an agglutinated mass of blood cells or bacteria, especially as an indicator of the presence of an antibody to them.

• 2a thick extra sole on a boot or shoe.

• 3the sound of heavy footsteps.

verb

• 1form into a clump or mass:the particles tend to clump together

• 2 (also clomp) walk with a heavy tread.