dense, heavy, impenetrable -- (permitting little if any light to pass through because of denseness of matter; "dense smoke"; "heavy fog"; "impenetrable gloom")
dense, thick -- (hard to pass through because of dense growth; "dense vegetation"; "thick woods")
dense -- (having high relative density or specific gravity; "dense as lead")
dense, dim, dull, dumb, obtuse, slow -- (slow to learn or understand; lacking intellectual acuity; "so dense he never understands anything I say to him"; "never met anyone quite so dim"; "although dull at classical learning, at mathematics he was uncommonly quick"- Thackeray; "dumb officials make some really dumb decisions"; "he was either normally stupid or being deliberately obtuse"; "worked with the slow students")
(Sound)
