Source : Webster's Revised Unabridged Dictionary (1913)

Aggress \Ag*gress"\, v. i. [imp. & p. p. {Aggressed}; p. pr. &
   vb. n. {Aggressing}.] [L. aggressus, p. p. of aggredi to go
   to, approach; ad + gradi to step, go, gradus step: cf. OF.
   aggresser. See {Grade}.]
   To commit the first act of hostility or offense; to begin a
   quarrel or controversy; to make an attack; -- with on.

Aggress \Ag*gress"\, v. t.
   To set upon; to attack. [R.]

Aggress \Ag*gress"\, n. [L. aggressus.]
   Aggression. [Obs.]

         Their military aggresses on others.      --Sir M. Hale.

Source : WordNet®

aggress
     v : take the initiative and go on the offensive; "The Serbs
         attacked the village at night"; "The visiting team
         started to attack" [syn: {attack}]