FLIGHTY
skittish, flighty, spooky, nervous
(adjective) unpredictably excitable (especially of horses)
flighty, flyaway, head-in-the-clouds, scatterbrained
(adjective) guided by whim and fancy; “flighty young girls”
Source: WordNet® 3.1
Etymology
Adjective
flighty (comparative flightier, superlative flightiest)
Given to unplanned and silly ideas or actions.
(of a bird) That flies easily or often.
(obsolete) Swift.
Source: Wiktionary
Flight"y, 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
Source: Webster’s Unabridged Dictionary 1913 Edition