Doesn't work around the greatest characters who don't have any illusions (8)
I believe the answer is:
realists
'characters who don't have any illusions' is the definition.
The definition and answer are not the same part of speech.
'doesn't work around the greatest' is the wordplay.
'doesn't work' becomes 'rests' (I can't justify this - if you can you should give a lot more credence to this answer).
'around' means one lot of letters goes inside another.
'the greatest' becomes 'ali' (film about Muhammad Ali).
'rests' enclosing 'ali' is 'REALISTS'.
Can you help me to learn more?
(Other definitions for realists that I've seen before include "They accept things as they are" , "Practical people without illusions" , "They see things as they are and act accordingly" .)