IPA: /ˈflaɪtiər/
KK: /ˈflaɪtɪər/
More likely to change quickly and unpredictably; not stable or reliable.
Her flightier moods made it hard for her friends to keep up with her.
Comparative: flightier
Superlative: flightiest
Flightier → It is formed from "flight" (from Old English "flyht", meaning the act of flying) and the suffix "-ier" (indicating a comparative form). The word "flightier" means more prone to flight or more restless than something else.
Think of the act of 'flying' ('flight') and how 'flightier' describes something that is more restless or prone to take off.