"Bare up under" is actually a phrase rather than a word. It means to endure or withstand something difficult or unpleasant. Antonyms for this phrase could be "surrender," "give in," "succumb," or "capitulate," which all suggest giving up or giving in to a challenging situation. Another antonym might be "avoid," which implies not having to face the difficulty altogether. However, it's important to note that sometimes the strongest choice is to bare up under a hardship and endure it with strength and resilience. It all depends on the situation and what the best course of action is for each individual.