Most dig at disturbed person expressing opinions arrogantly (9)
I believe the answer is:
dogmatist
'person expressing opinions arrogantly' is the definition.
I can't judge whether this definition defines the answer.
'most dig at disturbed' is the wordplay.
'disturbed' indicates anagramming the letters (the order of letters is disturbed).
'most'+'dig'+'at'='mostdigat'
'mostdigat' is an anagram of 'DOGMATIST'.
Can you help me to learn more?
(Other definitions for dogmatist that I've seen before include "opinionated type" , "bigot" , "stickler" .)