Life can be challenging, and we need as much fighting spirit as we can. We need it most, especially when we're about to do something hard like take a test or compete in a game. So this is where this Korean expression comes in.

Hwaiting (화이팅!) or sometimes also spelled phaiting (파이팅), is derived from the English word "fighting" that is an expression of encouragement. It means "Do your best!". It's a call to persevere. It's a way to get you pumped up and to lift the spirits of who you're telling it to. Koreans are very big on camaraderie and this commonly-used expression is proof of that. 

Here's a pronunciation guide you can use:

So whatever hard thing you have to do today, hwaiting! You can get through this!