Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means to attack, though it usually means to shoot, because that's a very common way in which to attack someone. Pow!

Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: Who are you going to shoot? You are going to shoot You (う). Why? Because there's another version of you in front of you, so if you don't shoot that version of you who is you, amirite?