Nouns

(n)bunch, clump, cluster, clusteringa grouping of a number of similar things“a bunch of trees”, “a cluster of admirers”
(n)ball, clod, glob, lump, clump, chunka compact mass“a ball of mud caught him on the shoulder”
(n)thump, thumping, clump, clunk, thuda heavy dull sound (as made by impact of heavy objects)

Verbs

(v)clop, clump, clunk, plunkmake or move along with a sound as of a horse's hooves striking the ground
(v)cluster, constellate, flock, clumpcome together as in a cluster or flock“The poets constellate in this town every summer”
(v)clump, clompwalk clumsily
(v)bunch, bundle, cluster, clumpgather or cause to gather into a cluster“She bunched her fingers into a fist”