Word of the Day (Dictionary.com, March 16, 2005)

fugacious \fyoo-GAY-shuhs\, adjective:

Lasting but a short time; fleeting. [...]

Fugacious is derived from Latin fugax, fugac-, "ready to flee,
flying; hence, fleeting, transitory," from fugere, "to flee,
to take flight." Other words derived from the same root
include fugitive, one who flees, especially from the law;
refuge, a place to which to flee back (re-, "back"), and hence
to safety; and fugue, literally a musical "flight."