Cluster (5)
'cluster' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for group that I've seen before include "Be exceptionally good" , "Set (of people)" , "Crew" , "Number or people or things classed together" , "Set; band" .)
'cluster' is the definition.
(bunching is a kind of clustering)
This is all the clue.
(Other definitions for bunch that I've seen before include "A cluster, group" , "Show silly fondness" , "Posy (of picked flowers)" , "Grouping of a number of similar things" , "Group (of bananas)" .)
'cluster' is the definition.
(synonyms)
This is all the clue.
(Other definitions for clump that I've seen before include "Clod, lump" , "Cluster of shrubs etc" , "Compacted mass" , "Bunch" , "Compact group of trees, for instance" .)