Mutable

Part of speech: adjective (a.)

1. Capable of alteration; subject to change; changeable in form, qualities, or nature. Things of the most accidental and mutable nature. South.

2. Changeable; inconstant; unsettled; unstable; fickle. "Most mutable wishes." Byron.

Synonyms: Changeable; alterable; unstable; unsteady; unsettled; wavering; inconstant; variable; fickle.