Definitions

1. adjective

most flighty or unpredictable in behavior, especially in a way that is considered amusing or charming

“She was known as the flightiest person in her social circle, always coming up with new and exciting plans.”

2. superlative of flighty

most flighty or unpredictable; most unstable or prone to change

“He was considered the flightiest member of the team, always changing his mind at the last minute.”