inconstant

Changing or varying, especially often and without discernible pattern or reason.

Fickle; faithless.

Not constant; subject to change; not firm; unsteady; fickle; capricious: said chiefly of persons.

Synonyms Unstable, vacillating, wavering, volatile, unsettled, uncertain.

Not constant; not stable or uniform; subject to change of character, appearance, opinion, inclination, or purpose, etc.; not firm; unsteady; fickle; changeable; variable; -- said of persons or things.