obtuseness

noun

having the quality of being obtuse

Wiktionary

noun

Etymology: Etymology tree English obtuse Proto-Germanic *-inōną Proto-Indo-European *-dyé- Proto-Germanic *-atjaną Proto-Indo-European *-tus Proto-Germanic *-þuz Proto-Germanic *-assuz Proto-Germanic *-inassuz Proto-West Germanic *-nassī Old English -nes Middle English -nesse English -ness English obtuseness From obtuse + -ness.

The quality of being obtuse.
Something that is obtuse.