throw in the towel

From the traditional signal from a boxer's support staff of throwing such an item into a boxing ring to indicate that the contestant cannot continue the match and is forfeiting to the opponent.

• "If their restaurant can't get business even on Mother's Day, it might be time for them to throw in the towel."
• "In short, there was so much space and so many things to shove things behind that most people, called on to find a silver cow-creamer there, would have said “Oh, what's the use?” and thrown in the towel."
• "One key imponderable is the attitude of the companies that will no longer have a role in the business. It is worth noting here that several have already thrown the towel in or been gently pushed out, such as Stagecoach and National Express."

• throw in the cards
• throw in the sponge
• throw up one's hands
• throw up the sponge

• throw to the dogs
• throw to the wolves