Fugacity

[fyoo-gey-shuh s] /fyuˈgeɪ ʃəs/

adjective
1.
fleeting; transitory:
a sensational story with but a fugacious claim on the public’s attention.
2.
Botany. falling or fading early.
/fjuːˈɡæsɪtɪ/
noun
1.
(thermodynamics) Also called escaping tendency. a property of a gas, related to its partial pressure, that expresses its tendency to escape or expand, given by d(logef) = dμ/RT, where μ is the chemical potential, R the gas constant, and T the thermodynamic temperature f
2.
the state or quality of being fugacious
/fjuːˈɡeɪʃəs/
adjective
1.
passing quickly away; transitory; fleeting
2.
(botany) lasting for only a short time: fugacious petals
adj.

“fleeing, likely to flee,” 1630s, from Latin fugaci-, stem of fugax “apt to flee, timid,” figuratively “transitory, fleeting,” from fugere “to flee” (see fugitive) + -ous. Related: Fugaciously; fugaciousness.

fugacity fu·gac·i·ty (fyōō-gās’ĭ-tē)
n.
A measure of the tendency of a substance, often a fluid, to move from one phase to another or from one site to another.