Since this word is made up of a single kanji, it should use the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word: You smell someone's icky (いき) breath. It's gross. Your skin crawls and your eyes roll back in your head from the icky, icky smell. You might die.
Your breath is so stinky that I could die.
You knocked the breath out of me!
Please do not breathe underwater.