The antonyms for the word "re-doubled" can be quite a few depending on the context of its usage. However, some of the common and obvious antonyms for the word "re-doubled" include reducing, diminishing, weakening, decreasing, lessening, and tapering off. These words indicate an opposite effect or action from what the word "re-doubled" implies. For instance, reducing means to make less, and weakening suggests a loss in strength. Therefore, depending on how the word "re-doubled" is used, it can have several opposite meanings, all of which suggest a reduction, diminishment, or decline.