rabbitbrush Syllabification: (rab·bit·brush)Pronunciation: /ˈrabitˌbrəSH/ (also rabbitbush /-ˌbo͝oSH/)Definition of rabbitbrush noun a shrub of the daisy family that bears clusters of pungent small yellow flowers, native to North America, especially the western US. Chrysothamnus nauseosus, family Compositae rabbitbrush in other Oxford dictionaries Definition of rabbitbrush in the British & World English dictionary