Underwoods are dense areas of trees or shrubs that grow on the forest floor, but there are multiple words that are synonymous with this term. The first synonym that comes to mind is the "underbrush", which is the shrubs and small plants that grow beneath the larger trees. Additionally, the word "brushwood" can also refer to the underwoods, but it generally describes the parts of the trees, such as branches and twigs, that are often used for fuel. Another related term is "thicket", which is a dense growth of small trees and bushes. Other synonyms for underwoods include coppice, copse, and boscage. All of these words describe the same thing- the dense wooded areas that grow beneath the taller trees of the forest.