Attack
noun, する verb
With aggression you attack the enemy. This is an attack.
こうげき
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
サーバーがサイバー攻撃を受けている。
The server is under cyber attack.
敵はまず巨大都市を攻撃してくるだろう。
The enemy will probably attack the megacities first.
昨日、武力攻撃が開始された。
Yesterday, an armed attack was launched.