Contrary directors, saying actor is better, show favouritism (4)
I believe the answer is:
bias
'favouritism' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for bias that I've seen before include "colour" , "Prejudice, partiality" , "A leaning or prejudice" , "Unfairly influence" , "Prejudice, one-sidedness" .)