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general::
Phrase(s): throw in the towel [and] throw in the sponge; toss in the sponge
Fig. (From boxing, where this is done by a boxer’s trainer to stop the fight.) to signal that one is going to quit; to quit. • When John could stand no more of Mary’s bad temper, he threw in the towel and left. • Don’t give up now! It’s too soon to throw in the sponge.
McGrawhill's American Idioms And Phrasal Verbs