obtuse
UK: əbˈtjuːs | US: əbˈtuːs
adj. slow to understand; lacking sharpness of intellect
adj. (of an angle) greater than 90° but less than 180°
adj. blunt or rounded in shape
Derived from Latin obtusus (past participle of obtundere, "to beat against"), combining ob- (against) and tundere (to beat). The original sense of "dulled by beating" evolved metaphorically to mean "blunt in perception" (16th century) and later "not sharp" in geometry (17th century). The word’s progression reflects a physical action (beating) abstracted into intellectual and geometric contexts.
His obtuse response frustrated the teacher.
An obtuse angle measures between 90° and 180°.
The knife’s obtuse edge made cutting difficult.
She feigned obtuseness to avoid the question.
The obtuse rock formation eroded into smooth curves.