changeful
/ˈtʃæŋfl/Definitions
1. adjective
liable or prone to change; having or showing a tendency to change often or suddenly
“The weather was changeful that day, with rain turning to sunshine and back to rain again.”
2. noun
a person or thing that is liable or prone to change; something that undergoes or shows change
“Her changeful moods made it difficult for her friends to understand her.”