Out of tune, qualitatively different (7)
I believe the answer is:
unequal
'different' is the definition.
(thesaurus)
'out of tune qualitatively' is the wordplay.
'out of' says the answer is hidden in the clue.
'UNEQUAL' is hidden in the letters of 'tune qualitatively'.
(Other definitions for unequal that I've seen before include "More or less" , "Not fair or balanced" , "Poorly balanced or matched" , "Not exactly matched" , "Differing" .)