Believe lecturer's cleared of deceit and bias (5)
I believe the answer is:
bevel
'bias' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for bevel that I've seen before include "Sloping edge or chamfer" , "Inclination of a surface" , "Tool for making a sloping edge on a piece of wood" , "Cant" , "Slanting surface" .)