obtuse
adj.
of an angle; between 90 and 180 degrees
adj.
(of a leaf shape) rounded at the apex
adj.
lacking in insight or discernment
too obtuse to grasp the implications of his behavior|a purblind oligarchy that flatly refused to see that history was condemning it to the dustbin
Synonym: purblind
adj.
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|dumb officials make some really dumb decisions|he was either normally stupid or being deliberately obtuse|worked with the slow students
Synonym: dense, dim, dull, dumb, slow
Antonym: acute