vi. 逐渐消失, 消散

[ verb ]
disappear gradually
<verb.change> blow over fade fleet pass pass off
The pain eventually passed off

Evanesce \Ev`a*nesce"\ ([e^]v`[.a]*n[e^]s"), v. i. [imp. & p. p.
{Evanesced} ([e^]v`[.a]*n[e^]st"); p. pr. & vb. n.
{Evanescing}. ([e^]v`[.a]*n[e^]s"s[i^]ng).] [L. evanescere; e
out + vanescere to vanish, fr. vanus empty, vain. See {Vain},
and cf. {Evanish}.]
To vanish away; to become dissipated and disappear, like
vapor.

I believe him to have evanesced or evaporated. --De
Quincey.