dense

adj

1.
permitting little if any light to pass through because of denseness of matter
heavy impenetrable
Derived from:
density
2.
hard to pass through because of dense growth
thick
Derived from:
denseness density
3.
having high relative density or specific gravity
Derived from:
denseness density
4.
slow to learn or understand; lacking intellectual acuity
dim dull dumb obtuse slow
Derived from:
denseness
5.
having component parts closely crowded together
thick