To throw in the towel means to give up on some endeavor, quit or abandon something, or admit defeat or failure. In boxing, a boxer’s trainer does this to stop the fight.

For example:

I’ve been working on this book for over a year, and I’m getting nowhere. I think I’m ready to throw in the towel.

After three hours of working on the leaky pipe, Josh decided to throw in the towel and try again later.

Harry threw in the towel after asking Larissa to go out to dinner three times without getting a “yes.”

Jason threw in the towel after hitting 200 golf balls and could not get even one of them straight.

Julie tried to light over 10 matches without succeeding, so she finally threw in the towel and went to find the lighter.

Tradução: jogar a toalha, desistir de fazer alguma coisa.

**Derivado do boxe, onde um técnico joga a toalha no ringue para sinalizar que a luta deve ser interrompida.