تسلیم شدن، سپر انداختن  
Throw in the towel     

Definition:     To quit. informal to admit that you have been defeated
تسلیم شدن، سپر انداختن

Example:   
1) The company threw in the towel after losing all of its major customers.

2) Mike 'Boom Boom' DeNola threw in the towel after three rounds. He'll probably have to spend a few days in the hospital, followed by a long convalescence in Miami.
تسلیم شدن_Throw in the towel

3) I was ready to throw in the towel, but I stayed with it.
می خواستم تسلیم بشم اما طاقت آوردم.

4) He’s not a quitter, so he’s not going to throw in the towel.

ََA short conversation with Throw 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."


Etymology:     This phrase comes from boxing. When a boxer is too beat up to continue, his coach throws a towel into the ring to signal that the fight is over.