Somewhat malign or antagonistic but uninformed (8)
I believe the answer is:
ignorant
'uninformed' is the definition.
(thesaurus)
'somewhat malign or antagonistic' is the wordplay.
'somewhat' indicates the answer is hidden within the clue.
'IGNORANT' can be found hidden inside 'malign or antagonistic'.
'but' acts as a link.
(Other definitions for ignorant that I've seen before include "Knowing nothing" , "Uneducated" , "Rude or knowing very little" , "left in the dark" , "Unaware, uninformed" .)