Most just stare if confused (7)
I believe the answer is:
fairest
'most just' is the definition.
('fair' is associated in meaning with 'just')
'stare if confused' is the wordplay.
'confused' indicates anagramming the letters.
'stare'+'if'='stareif'
'stareif' with letters rearranged gives 'FAIREST'.
(Other definitions for fairest that I've seen before include "'''Mirror, mirror on the wall, who is the ... of them all'' (Snow White's stepmother) (7)'" , "Most beautiful" , "Very lovely" .)