Holding unreasonable beliefs, a medley of merest mix (9)
I believe the answer is:
extremism
'holding unreasonable beliefs a' is the definition.
I can't judge whether this defines the answer.
'medley of merest mix' is the wordplay.
'medley of' is an anagram indicator (I've seen 'medley' mean this).
'merest'+'mix'='merestmix'
'merestmix' is an anagram of 'EXTREMISM'.
Can you help me to learn more?
(Other definitions for extremism that I've seen before include "Ultra-radical views" , "The holding of way-out ideas" , "Radical political belief" , "The holding of far from moderate views" , "Immoderate political action" .)