Flibbertigibbet / FLIB-ur-tee-jib-it / noun:
A silly, flighty, or scatterbrained person, especially a pert young woman with such qualities.
We discovered here not the flibbertigibbet Connolly describes but a serious reader (Goethe, Tolstoy, Proust) who found her cultural ideal in the 18th-century France.
-- Martin Stannard, "Enter Shrieking", New York Times, November 28, 1993
He argues persuasively that Millay's reputation has been harmed not only by academics who dread and fear her heartfelt "simplicity," but by the very admirers who wished to promote her as a kind of whimsical flibbertigibbet, a peotical Anne of Green Gables.
-- Liz Rosenberg, "So Young, So Good, So Popular", New York Times, March 15, 1992
That it was the Owenses who had got involved in this nonsense, rather than some flibbertigibbet johnny-come-latelies, counted for a lot, for the Owenses were respectable and respected.
-- Neil Gaiman and Dave Mckean, The Graveyard Book