WordWeb Online

1. A grouping of a number of similar things
   - bunch, cluster, clustering
    
2. A compact mass
   - ball, clod, glob, lump, chunk
    
3. A heavy dull sound (as made by impact of heavy objects)
   - thump, thumping, clunk, thud, clonk

1. Make or move along with a sound as of a horse's hooves striking the ground
   - clop, clunk, plunk
    
2. Come together as in a cluster or flock
   - cluster, constellate, flock
    
3. Walk clumsily
   - clomp
    
4. Gather or cause to gather into a cluster
   - bunch, bunch up, bundle, cluster

Derived forms: clumped, clumps, clumping

Type of: agglomeration, assemble, foregather, forgather, form, gather, go, meet, sound, walk