throw in the towel
to stop trying to do something because you know that you cannot succeed

[TahlilGaran] Dictionary of Contemporary English ▲

throw in the towel
[informal]
to stop trying to do something because you know that you cannot succeed.
Three of the original five candidates have now thrown in the towel.

to admit defeat or failure.
The union was forced to throw in the towel and settle their bitter dispute with the company.

Etymology: based on the literal meaning of throwing a towel into the ring in boxing (= signaling that a fighter can no longer continue by throwing a towel into the area where the fight takes place)

[TahlilGaran] English Idioms Dictionary ▲

throw in the towel
• throw in the towel/sponge
to surrender, to give up; admit defeat, stop fighting (in a boxing match a towel is thrown into the ring to admit defeat)
The candidate threw in the towel early in the evening of the election when it became impossible for her to win.

The boxer threw in the towel about halfway through the match.

[TahlilGaran] English Idioms Dictionary ▲

throw in the towel
v. phr., informal To admit defeat; accept loss.
After taking a beating for five rounds, the fighter's seconds threw in the sponge.
When Harold saw his arguments were not being accepted, he threw in the towel and left.
Synonym: GIVE UP.

[TahlilGaran] English Idioms Dictionary ▲