What does aggress mean?
The definition of 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.

Ag*gress”, n. [L. aggressus.]
Aggression. [Obs.]
Their military aggresses on others. Sir M. Hale.

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