obtuse
UK[əbˈtjuːs]US[əbˈtuːs]
adj
annoyingly slow to understand; lacking sharpness or quickness of intellect
adj
(of an angle) more than 90° and less than 180°
adj
not sharp-pointed or sharp-edged; blunt
Morpheme Breakdown
ob
tuse
ob
against, completely
tuse
to beat
Etymology
the word 'obtuse' originates from the latin 'obtusus', the past participle of 'obtundere', meaning 'to beat against' or 'to blunt'. the literal sense of 'beaten against' evolved into the meaning 'dulled' or 'not sharp', first applied to physical objects. this concrete meaning of bluntness was then metaphorically extended to describe a dull or slow mind, and was also adopted into geometry to describe an angle that is not sharp. the semantic journey is from a physical action of beating to a state of being dulled, and finally to abstract intellectual and geometric properties.
Analysis
Structure: ob (against, completely) + tuse (to beat)
'ob-' is a latin prefix meaning 'against, toward, completely'. 'tuse' is from the latin past participle stem 'tus-' of the verb 'tundere', meaning 'to beat'.
Examples
she was being deliberately obtuse, refusing to understand the simple instructions.
an obtuse angle measures between 90 and 180 degrees.
the obtuse tip of the tool made it unsuitable for detailed work.