Source : Webster's Revised Unabridged Dictionary (1913)

Assailant \As*sail"ant\, a. [F. assaillant, p. pr. of
   assaillir.]
   Assailing; attacking. --Milton.

Assailant \As*sail"ant\, n. [F. assaillant.]
   One who, or that which, assails, attacks, or assaults; an
   assailer.

         An assailant of the church.              --Macaulay.

Source : WordNet®

assailant
     n : someone who attacks [syn: {attacker}, {aggressor}, {assaulter}]