Opinion that may be obtuse (5)
I believe the answer is:
angle
I believe this is a double definition.
'opinion' is the first definition.
(I've seen this before)
'that may be obtuse' is the second definition.
(I know that angle are often obtuse)
(Other definitions for angle that I've seen before include "Perspective" , "The space where two lines intersect" , "Fish with hook and line" , "old invader" , "Corner - fish" .)