To Rescue
To Save
transitive verb, godan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means rescue so the verb vocab version is to rescue or to save.
救う is a relatively formal word for saving someone from a dangerous or difficult situation, like 命を救う (save someone's life) or 心を救う (save someone emotionally). It's usually reserved for particularly significant or meaningful contexts, like heroes saving the world or people being saved from deep suffering or extreme hardship.
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:
When disaster strikes, the first place you should go to rescue people is a school (すく) . You need to save all those innocent, adorable schoolchildren! Can you imagine how mad everyone would be if you skipped over a school and went to rescue people at a law firm or something? No, a school is definitely the place you've got to rescue first.
命を救う
to save a life
人を救う
to save someone
世界を救う
to save the world
地球を救う
to save the earth
危機を救う
to avert a crisis
彼らは人々を救うために、毎日働いています。
They work every day to save people.
地元のボランティアが多くの命を救いました。
Local volunteers saved many lives.
あなたが私を救ってくれたから、今の私がいるんです。
I'm the person I am today because you saved me.
救急車が来るまで、彼を救うためにできることをしていました。
I did everything I could to save him until the ambulance arrived.