Source : Webster's Revised Unabridged Dictionary (1913)

Assassinate \As*sas"sin*ate\, v. t. [imp. & p. p.
   {Assassinated}; p. pr. & vb. n. {Assassinating}.] [LL.
   assassinatus, p. p. of assassinare.]
   1. To kill by surprise or secret assault; to murder by
      treacherous violence.

            Help, neighbors, my house is broken open by force,
            and I am ravished, and like to be assassinated.
                                                  --Dryden.

   2. To assail with murderous intent; hence, by extended
      meaning, to maltreat exceedingly. [Archaic]

            Your rhymes assassinate our fame.     --Dryden.

            Such usage as your honorable lords Afford me,
            assassinated and betrayed.            --Milton.

   Syn: To kill; murder; slay. See {Kill}.

Assassinate \As*sas"sin*ate\, n. [F. assassinat.]
   1. An assassination, murder, or murderous assault. [Obs.]

            If I had made an assassinate upon your father. --B.
                                                  Jonson.

   2. An assassin. [Obs.] --Dryden.

Source : WordNet®

assassinate
     v 1: murder; especially of socially prominent persons; "Anwar
          Sadat was assassinated because many people did not like
          his peace politics with Israel"
     2: destroy or damage seriously, as of someone's reputation; "He
        assassinated his enemy's character"