Fickle (7)
(Other definitions for erratic that I've seen before include "Rambling" , "Shifting like Cartier" , "Shifting, unpredictable" , "Irregular or uneven in movement or habit" , "Cartier (anag.)" .)
'fickle' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for flighty that I've seen before include "Changeable" , "Giddy-minded" , "rather impetuous?" , "Capricious" , "as a bird?" .)
'fickle' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for mutable that I've seen before include "not being fixed" , "Liable to change, fickle" , "It might change!" , "Inconsistent" , "not stuck down" .)
(Another definition for changeable that I've seen is " Subject to alteration".)
'fickle' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for inconstant that I've seen before include "Often changing" , "Variable, irregular" , "Fickle" .)