Any confusion? Horribly easy, right, for pessimist? (8)
I believe the answer is:
naysayer
'pessimist?' is the definition.
(thesaurus)
'any confusion? horribly easy right' is the wordplay.
'confusion?' is an anagram indicator (I've seen 'confusion' mean this).
'horribly' indicates an anagram.
'right' becomes 'r' (common abbreviation).
'any' is an anagram of 'nay'.
'easy' is an anagram of 'saye'.
'nay'+'saye'+'r'='NAYSAYER'
'for' acts as a link.
(Other definitions for naysayer that I've seen before include "He refuses to agree" , "One who denies" , "Obstructionist" , "Yes, Aryan may be person who habitually denies or refuses" .)