Joiner's instrument giving angles that aren't right (5)
I believe the answer is:
bevel
This clue might be a double definition.
'joiner's' is the first definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'instrument giving angles that aren't right' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?
Can you help me to learn more?
(Other definitions for bevel that I've seen before include "Slant of surface" , "Inclination of a surface" , "Sloping surface or edge" , "Two flat surfaces meeting at other than a right angle" , "Sloping edge or chamfer" .)