early 15c., from Middle French dense and directly from Latin densus "thick, crowded; cloudy," perhaps from PIE root *dens- "dense, thick" (cognates: Greek dasus "hairy, shaggy"). Sense of "stupid" is first recorded 1822.
1. Dense smoke swirled and billowed, its rank fumes choking her.
2. His prose is vigorous and dense, occasionally to the point of obscurity.
3. They walked through the dense Mozambican bush for thirty six hours.
4. Twenty million years ago, Idaho was populated by dense primordial forest.
5. Where Bucharest now stands, there once was a large, dense forest.