'Underbrush' definitions:

Definition of 'underbrush'

From: WordNet
noun
The brush (small trees and bushes and ferns etc.) growing beneath taller trees in a wood or forest [syn: underbrush, undergrowth, underwood]

Definition of 'Underbrush'

From: GCIDE
  • Underbrush \Un"der*brush`\, n. Shrubs, small trees, and the like, in a wood or forest, growing beneath large trees; undergrowth. [1913 Webster]