noun

• An attempt to cause damage, injury to, or death of an opponent or enemy.
  "Combat in Mimesis Online is nice and simple. You click on your target […] and then keep right-clicking your chosen attack from the drop down menu. Every time you right click on the attack, your character will swing, shoot, etc."
• (informal, by extension) The beginning of active operations on anything.
  "Having washed the plates from dinner, I made an attack on the laundry."
• (computing) An attempt to exploit a vulnerability in a computer system.
  "birthday attack; denial-of-service attack"
• (cricket) Collectively, the bowlers of a cricket side.

verb

• (transitive) To apply violent force to someone or something.
  "This species of snake will only attack humans if it feels threatened."
• (transitive) 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."
• (transitive) To begin to affect; to act upon injuriously or destructively; to begin to decompose or waste.
  "On the fourth of March he was attacked by fever."
• (transitive) To deal with something in a direct way; to set to work upon.
  "We’ll have dinner before we attack the biology homework."