What does "inconstant" mean?

Inconstant: 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; as, inconstant in love or friendship. "The inconstant moon." Shak. While we, inquiring phantoms of a day, Inconstant as the shadows we survey! Boyse.