The phrase "take up on oneself" refers to assuming responsibility for something or making a commitment. Antonyms for this phrase include "abdicate," "avoid," and "neglect." To abdicate is to relinquish responsibility or renounce a position of authority. Avoidance involves intentionally staying away from or disregarding a task or responsibility, while neglect is a failure to give necessary attention or care. Additional antonyms include "reject," "decline," "refuse," "shun," and "evade." Each of these words carries a sense of rejecting or disassociating oneself from the task or responsibility in question.