Webster's Revised Unabridged Dictionary · 1913

Inconstant

Inconstant , adjective

[Latin inconstans: compare French inconstant. See In- not, and Constant.]

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. — Shakespeare
While we, inquiring phantoms of a day, Inconstant as the shadows we survey! — Boyse