Unpredictable, temperamental (7)
I believe the answer is:
erratic
I believe this clue is a double definition.
'unpredictable' is the first definition.
(synonyms)
'temperamental' is the second definition.
(I know that temperamental can be written as erratic)
(Other definitions for erratic that I've seen before include "Hit-or-miss" , "Rambling" , "Unpredictable - car tire (anag)" , "hit-and-miss" , "Variable" .)