INCONSTANT
inconstant
(adjective) likely to change frequently often without apparent or cogent reason; variable; “inconstant affections”; “an inconstant lover”; “swear not by...the inconstant moon”- Shakespeare
Source: WordNet® 3.1
Etymology
Adjective
inconstant (comparative more inconstant, superlative most inconstant)
Not constant; wavering.
Unfaithful to a lover.
Source: Wiktionary
In*con"stant, a. Etym: [L. inconstans: cf. F. inconstant. See In-
not, and Constant.]
Definition: 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.
Syn.
– Mutable; fickle; volatile; unsteady; unstable; changeable;
variable; wavering; fluctuating.
Source: Webster’s Unabridged Dictionary 1913 Edition