obtuse

adj

1.
of an angle; between 90 and 180 degrees
Antonym:
acute
2.
(of a leaf shape) rounded at the apex
Derived from:
obtuseness
3.
lacking in insight or discernment
purblind
Derived from:
obtuseness
4.
slow to learn or understand; lacking intellectual acuity
dense dim dull dumb slow
Derived from:
obtuseness