Source : Webster's Revised Unabridged Dictionary (1913)

Antibacterial \An`ti*bac*te"ri*al\, a. (Med.)
   (a) Inimical to bacteria; -- applied esp. to serum for
       protection against bacterial diseases.
   (b) Opposed to the bacterial theory of disease.

Source : WordNet®

antibacterial
     adj : destroying bacteria or inhibiting their growth

antibacterial
     n : any drug that destroys bacteria or inhibits their growth
         [syn: {antibacterial drug}, {bactericide}]