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Webster 1913 Edition
Obtuseness
Ob-tuse′ness
,Noun.
 State or quality of being obtuse. 
Webster 1828 Edition
Obtuseness
OBTU'SENESS
, n.1.
  Bluntness; as the obtuseness of an edge or a point.2.
  Dullness; want of quick sensibility; as the obtuseness of the senses.3.
  Dullness of sound.