to set upon in a forceful, violent, hostile, or aggressive way, with or without a weapon; begin fighting with

He attacked him with his bare hands.

to begin hostilities against; start an offensive against

to attack the enemy.

to blame or abuse violently or bitterly.

to direct unfavorable criticism against; criticize severely; argue with strongly

He attacked his opponent's statement.

to try to destroy, esp. with verbal abuse

to attack the mayor's reputation.

to set about (a task) or go to work on (a thing) vigorously

to attack housecleaning; to attack the hamburger hungrily.

(of disease, destructive agencies, etc.) to begin to affect.

to make an attack; begin hostilities.

the act of attacking; onslaught; assault.

a military offensive against an enemy or enemy position.

Pathology . seizure by disease or illness

an attack of indigestion.

the beginning or initiating of any action; onset.

an aggressive move in a performance or contest.

the approach or manner of approach in beginning a musical phrase.

adjective

assailable , pregnable , vincible