The phrase 'deep-sixes' refers to getting rid of someone or something permanently. Antonyms for the term would indicate ways to keep or preserve someone or something. Synonyms for preservation include retain, conserve and protect. Antonyms of 'deep-sixes' could also include phrases like rescue, save, or resurrect. Refraining from disposing of someone, object or idea would express the opposite meaning to 'deep-sixes'. Antonyms further extend to various derivatives such as salvage, recover, rescue, and redeem. While antonyms by definition convey diverse meanings, in the case of 'deep-sixes' indicate the opposite action of tossing or discarding something.