Flighty

Part of speech: adjective (a.)

1. Fleeting; swift; transient. The flighty purpose never is o'ertook, Unless the deed go with it. Shak.

2. Indulging in flights, or wild and unrestrained sallies, of imagination, humor, caprice, etc.; given to disorder Proofs of my flighty and paradoxical turn of mind. Coleridge. A harsh disciplinarian and a flighty enthusiast. J. S. Har