What might give an obtuse result? (10)
I believe the answer is:
protractor
'result?' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
I don't understand the remainder of the clue.
(Other definitions for protractor that I've seen before include "muscle" , "Geometry set item" , "Geometrical instrument" , "Angle-measuring device" , "draughtsman may use this" .)