a. 逐渐消失的, 容易消散的, 短暂的

[医] 易消灭的, 渐消失的, 挥发性的

[ adj ]
tending to vanish like vapor
<adj.all>
evanescent beauty

Evanescent \Ev`a*nes"cent\, a. [L. evanescens, -entis, p. pr. of
evanescere.]
1. Liable to vanish or pass away like vapor; vanishing;
fleeting; as, evanescent joys.

So evanescent are the fashions of the world in these
particulars. --Hawthorne.

2. Vanishing from notice; imperceptible.

The difference between right and wrong, in some
petty cases, is almost evanescent. --Wollaston.