To apply violent force to someone or something.

"This species of snake will only attack humans if it feels threatened."

To aggressively challenge a person, idea, etc., with words (particularly in newspaper headlines, because it typesets into less space than "criticize" or similar).

"She published an article attacking the recent pay cuts."

To begin to affect; to act upon injuriously or destructively; to begin to decompose or waste.

To deal with something in a direct way; to set to work upon.

"I attacked the meal with a hearty appetite."

To aim balls at the batsman’s wicket.

To set a field, or bowl in a manner designed to get wickets.

To bat aggressively, so as to score runs quickly.

To move forward in an active attempt to score a point, as opposed to trying not to concede.

To accelerate quickly in an attempt to get ahead of the other riders.

Carrying out an attack.