blowing hot and cold (6)
I believe the answer is:
fickle
'blowing hot and cold' is the definition.
(personally unpredictable)
This is all the clue.
(Other definitions for fickle that I've seen before include "Inconstant, changeable" , "Subject to changes of mind" , "Erratic, unpredictable" , "Having changing loyalties" , "Inconstant in affections" .)