Mercurian

Example:She has a mercurial personality, one moment she's cheerful and the next she's gloomy.

Definition:Impulsive, changeable, and unpredictable; relating to or characteristic of the planet Mercury or its deity in mythology.

Example:The strategy employs a hermesian approach to problem-solving, utilizing swift and clever tactics.

Definition:Relating to or characterized by the attributes of Hermes, the Greek messenger god (although not common usage).