Source : Webster's Revised Unabridged Dictionary (1913)

Premeditate \Pre*med"i*tate\, v. t. [imp. & p. p. {Premeditated}
   (-t[=a]`t?d); p. pr. & vb. n. {Premeditating}.] [L.
   praemeditatus, p. p. of praemeditari; prae before + meditari
   to meditate. See {Meditate}.]
   To think on, and revolve in the mind, beforehand; to contrive
   and design previously; as, to premeditate robbery.

         With words premeditated thus he said.    --Dryden.

Source : WordNet®

premeditated
     adj : characterized by deliberate purpose and some degree of
           planning; "a premeditated crime" [ant: {unpremeditated}]