Meaning/Usage: Give up; quit; surrender
Explanation: When a boxer was getting beaten so badly, the coach or manager would throw a towel in to stop the fight. This phrase can be used outside of boxing to simply express quitting.
"I was ready to throw in the towel, but I stayed with it."
"He's not a quitter, so he's not going to throw in the towel."
"I saw a fight last almost two hours before one guy threw in the towel."
A: "The boxing match is great."
B: "One guy is really getting beat up."
A: "Do you think he's going to give up?"
B: "He's not going to throw in the towel, they rarely do that these days."
Other Common Sentences
"There's no chance for me to win. I'm calling it quits."
"I don't think I can win, so I'm going to give up."
"I'd rather surrender than get the hell beaten out of me."