Antonyms are words that have the opposite meaning of another word. The phrase 'bring up short' means to stop or interrupt someone suddenly. The antonyms for this phrase could be 'keep going' or 'allow to continue'. Other antonyms might include 'lengthen' or 'prolong', which mean to make something longer or to continue it for a longer period of time. 'Smooth out' and 'ease into' might also be antonyms, as they suggest a more gradual approach to something, rather than abruptly stopping it. Ultimately, antonyms for the phrase 'bring up short' will depend on the context and the specific meaning of the phrase in each situation.