What is the meaning of clumping?

noun

• The sound of a horse's hoofs hitting on a hard surface.
  • synonyms: clip-clop, clippety-clop, clop, clopping, clunking

verb

• Make or move along with a sound as of a horse's hooves striking the ground.
  • synonyms: clop, clump, clunk, plunk
• Come together as in a cluster or flock.
  • usage: "The poets constellate in this town every summer"
  • synonyms: cluster, constellate, flock, clump
• Walk clumsily.
  • synonyms: clump, clomp
• Gather or cause to gather into a cluster.
  • usage: "She bunched her fingers into a fist"
  • synonyms: bunch, bunch up, bundle, cluster, clump