v. t. [ imp. & p. p. Attacked p. pr. & vb. n. Attacking. ] [ F. attaquer, orig. another form of attacher to attack: cf. It. attacare to fasten, attack. See Attach, Tack a small nail. ] 1. To fall upon with force; to assail, as with force and arms; to assault. “Attack their lines.” Dryden. [ 1913 Webster ]

2. To assail with unfriendly speech or writing; to begin a controversy with; to attempt to overthrow or bring into disrepute, by criticism or satire; to censure; as, to attack a man, or his opinions, in a pamphlet. [ 1913 Webster ]

3. To set to work upon, as upon a task or problem, or some object of labor or investigation. [ 1913 Webster ]

4. To begin to affect; to begin to act upon, injuriously or destructively; to begin to decompose or waste. [ 1913 Webster ]

On the fourth of March he was attacked by fever. Macaulay. [ 1913 Webster ]

Hydrofluoric acid . . . attacks the glass. B. Stewart. [ 1913 Webster ]

Syn. -- To Attack, Assail, Assault, Invade. These words all denote a violent onset; attack being the generic term, and the others specific forms of attack. To attack is to commence the onset; to assail is to make a sudden and violent attack, or to make repeated attacks; to assault (literally, to leap upon) is to attack physically by a had-to-hand approach or by unlawful and insulting violence; to invade is to enter by force on what belongs to another. Thus, a person may attack by offering violence of any kind; he may assail by means of missile weapons; he may assault by direct personal violence; a king may invade by marching an army into a country. Figuratively, we may say, men attack with argument or satire; they assail with abuse or reproaches; they may be assaulted by severe temptations; the rights of the people may be invaded by the encroachments of the crown. [ 1913 Webster ]

v. i. To make an onset or attack. [ 1913 Webster ]

n. [ Cf. F. attaque. ] 1. The act of attacking, or falling on with force or violence; an onset; an assault; -- opposed to defense. [ 1913 Webster ]

2. An assault upon one's feelings or reputation with unfriendly or bitter words. [ 1913 Webster ]

3. A setting to work upon some task, etc. [ 1913 Webster ]

4. An access of disease; a fit of sickness. [ 1913 Webster ]

5. The beginning of corrosive, decomposing, or destructive action, by a chemical agent. [ 1913 Webster ]

a. Capable of being attacked. [ 1913 Webster ]

adj. affected by disease.
Syn. -- infected. [ WordNet 1.5 ]

n. One who attacks. [ 1913 Webster ]