obtuse in WordNet English dictionary

1. slow to learn or understand; lacking intellectual acuity
   "so dense he never understands anything I say to him"; "never met anyone quite so dim"; "although dull at classical learning, at mathematics he was uncommonly quick"- Thackeray; "dumb officials make some really dumb decisions"; "he was either normally stupid or being deliberately obtuse"; "worked with the slow students"
   dense  dim  dull  dumb  obtuse  slow 
   
2. of an angle; between 90 and 180 degrees
   obtuse 
   
3. (of a leaf shape) rounded at the apex
   obtuse 
   
4. lacking in insight or discernment
   "too obtuse to grasp the implications of his behavior"; "a purblind oligarchy that flatly refused to see that history was condemning it to the dustbin"- Jasper Griffin
   obtuse  purblind