evanesce

from WordNet (r) 3.0 (2006)

evanesce
    v 1: disappear gradually; "The pain eventually passed off" [syn:
         {evanesce}, {fade}, {blow over}, {pass off}, {fleet},
         {pass}]

from The Collaborative International Dictionary of English v.0.48

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.
   [1913 Webster]

         I believe him to have evanesced or evaporated. --De
                                                  Quincey.
   [1913 Webster]