attack

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To set upon with violent force.
• intransitive verb To criticize strongly or in a hostile manner.
• intransitive verb To start work on with purpose and vigor.
• intransitive verb To act on in a detrimental way; cause harm to.
• intransitive verb To play (the ball) aggressively, especially by moving toward it rather than by waiting for it to arrive.
• intransitive verb To move toward (the goal) on an offensive play, as in lacrosse.
• intransitive verb In volleyball, to hit (the ball) forcefully over the net.
• intransitive verb To make a sudden, intense effort to pass (a competitor in a race).
• intransitive verb To make an attack; launch an assault.
• intransitive verb To make a play on offense; attempt to score.
• intransitive verb To make a sudden, intense effort to pull ahead in a race.
• noun The act or an instance of attacking; an assault.
• noun An expression of strong criticism; hostile comment.
• noun Offensive play, especially in lacrosse.
• noun An offensive play.
• noun The players executing such a play.
• noun Scoring ability or potential.
• noun A forceful shot over the net in volleyball.
• noun A sudden, intense effort to pull ahead in a race.
• noun The initial movement in a task or undertaking.
• noun A method or procedure.
• noun An episode or onset of a disease, especially an occurrence of a chronic disease.
• noun The experience or beginning of a feeling, need, or desire.
• noun Music The beginning or manner of beginning a piece, passage, or tone.
• noun Decisiveness and clarity in artistic expression.

from The Century Dictionary.

• To assault; fall upon with force; assail, as with force and arms; begin hostilities against.
• To endeavor to injure, overthrow, or bring into discredit by any act or proposal, or by unfriendly words or writing, whether by satire, calumny, criticism, or argument: as, to attack a religious belief or a legislative measure; to attack a man or his opinions in a newspaper.
• To make an onset or attempt upon, in a general sense; begin action upon or in regard to; set about or upon: as, to attack a piece of work or a problem, or (humorously) the dinner.
• To begin to affect; come or fall upon; seize: said of diseases and other destructive agencies: as, yesterday he was attacked by fever; caries attacked the bones; locusts attacked the crops. Specifically In chem., to cause to decompose or dissolve.
• Synonyms Set upon, Fall upon, etc. (see assail), assault, beset, besiege, beleaguer, charge upon, engage, challenge, combat. To impugn, criticize, censure.
• To make an attack or onset: as, the enemy attacked with great boldness.
• noun A falling on with force or violence, or with calumny, satire, or criticism; an onset; an assault.
• noun Battle generally; fight.
• noun An onset of any kind; the initial movement in any active proceeding or contest, as a game of chess, cricket, etc.; in music, specifically, the act (with reference to the manner) of beginning a piece, passage, or phrase, especially by an orchestra.
• noun The aggressive part of the art of fencing: opposed to defense.
• noun A seizure by a disease; the onset of a disease.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To make an onset or attack.
• noun The act of attacking, or falling on with force or violence; an onset; an assault; -- opposed to defense.
• noun An assault upon one's feelings or reputation with unfriendly or bitter words.
• noun A setting to work upon some task, etc.
• noun An access of disease; a fit of sickness.
• noun The beginning of corrosive, decomposing, or destructive action, by a chemical agent.
• transitive verb To fall upon with force; to assail, as with force and arms; to assault.
• transitive verb 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.
• transitive verb To set to work upon, as upon a task or problem, or some object of labor or investigation.