The Collaborative International Dictionary of English v.0.48:

Thunderstrike \Thun"der*strike`\, v. t. [imp. Thunderstruck;
   p. p. Thunderstruck, -strucken; p. pr. & vb. n.
   Thunderstriking.]
   1. To strike, blast, or injure by, or as by, lightning. [R.]
      --Sir P. Sidney.
      [1913 Webster]

   2. To astonish, or strike dumb, as with something terrible;
      -- rarely used except in the past participle.
      [1913 Webster]

            drove before him, thunderstruck.      --Milton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

thunderstruck
    adj 1: as if struck dumb with astonishment and surprise; "a
           circle of policement stood dumbfounded by her denial of
           having seen the accident"; "the flabbergasted aldermen
           were speechless"; "was thunderstruck by the news of his
           promotion" [syn: dumbfounded, dumfounded,
           flabbergasted, stupefied, thunderstruck,
           dumbstruck, dumbstricken]