To be fair, don't fail the clever ones (8)
I believe the answer is:
passable
'to be fair' is the definition.
('passable' can be a synonym of 'fair')
'don't fail the clever ones' is the wordplay.
I cannot quite see how this works, but
'clever' could be 'able' (able can mean skilled or talented) and 'able' is located in the answer.
The remaining letters 'pass' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for passable that I've seen before include "Good enough to be acceptable" , "All right" , "okay?" , "OK" , "Fair" .)