The phrase "settling up on" typically refers to resolving a debt, paying for something, or reaching an agreement. Antonyms for this expression would include avoiding, evading, ignoring, abandoning, or rejecting the responsibility of settling up on a debt or agreement. In other words, one could simply choose to walk away from the situation or refuse to take action. Alternatively, one may negotiate or compromise, agreeing on a different course of action that satisfies both parties. Whatever the case may be, the antonyms for "settling up on" reflect a range of attitudes and behaviors towards responsibility and accountability.