fyüˈgasəd.ē noun
( -es )
Etymology: from fugacious, after such pairs as English capacious: capacity
1. : lack of enduring qualities : transience
that the fresh bloom of the carol was evanescent … I always knew; but never realized its extreme fugacity until five years ago — A.T.Quiller-Couch
2.
a. : the vapor pressure of a vapor assumed to be an ideal gas obtained by correcting the determined vapor pressure and useful as a measure of the escaping tendency of a substance from a heterogeneous system
b. : a correction for the deviation in the behavior of an actual solution from that of an ideal solution — compare activity 6b