What's known by expert holding irrational beliefs? (8)
I believe the answer is:
opinions
'beliefs?' is the definition.
(opinion is a kind of belief)
'what's known by expert holding irrational' is the wordplay.
'what's known by expert' becomes 'onions' (I can't explain this - if you can you should believe this answer much more).
'holding' means one lot of letters goes inside another.
'irrational' becomes 'pi' (an irrational number).
'onions' enclosing 'pi' is 'OPINIONS'.
Can you help me to learn more?
(Other definitions for opinions that I've seen before include "ideas" , "'Beliefs, convictions (8)'" , "Points of view, judgments" , "Viewpoints" , "Macbeth bought golden ones" .)