Outdare is a challenging word to find antonyms for. However, there are some options that work. Some antonyms include "yield," "concede," and "surrender." These words imply backing down or giving in, rather than standing up to a challenge. Another suitable antonym is "avoid," which suggests avoiding the possibility of facing a challenge altogether. Additionally, "shy away" and "refrain" could be used as antonyms, conveying a hesitation or reluctance to face a dare or challenge. Lastly, "comply" and "conform" could be used as antonyms of outdare, suggesting following rules or social norms rather than taking a daring action.