The Collaborative International Dictionary of English v.0.48:

Obtuse \Ob*tuse"\ a. [Compar. Obtuser; superl. Obtusest.]
   [L. obtusus, p. p. of obtundere to blunt: cf. F. obtus. See
   Obtund.]
   1. Not pointed or acute; blunt; -- applied esp. to angles
      greater than a right angle, or containing more than ninety
      degrees.
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   2. Not having acute sensibility or perceptions; not alert,
      especially to the feelings of others; dull; stupid; as,
      obtuse senses. --Milton.
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   3. Dull; deadened; as, obtuse sound. --Johnson.
      [1913 Webster] Obtuse-angled