Most just fine with quirky satire (7)
I believe the answer is:
fairest
'most just' is the definition.
('fair' can be a synonym of 'just')
'fine with quirky satire' is the wordplay.
'fine' becomes 'f' (abbreviation).
'with' says to put letters next to each other.
'quirky' is an anagram indicator.
'satire' anagrammed gives 'airest'.
'f'+'airest'='FAIREST'
(Other definitions for fairest that I've seen before include "Very lovely" , "'''Mirror, mirror on the wall, who is the ... of them all'' (Snow White's stepmother) (7)'" , "Most beautiful" .)