Obtuseness
Part of speech: noun
Definition: Something that is obtuse
Dullness
Part of speech: noun
Definition: The quality of being slow to understand things.The quality of being uninteresting.The lack of visual brilliance.bluntness.
Example sentence: Dullness in matters of government is a good sign, and not a bad one - in particular, dullness in parliamentary government is a test of its excellence, an indication of its success.