The phrase "set up on" refers to the act of establishing or preparing for a particular purpose. Antonyms for "set up on" can be any action or term that defines the opposite of it. Some antonyms for "set up on" could be tear down, break apart, destroy, dismantle, remove, eliminate. For example, if you're thinking of setting up on a big project, your antonyms could be to break it apart or tear it down into smaller, more manageable pieces. These antonyms can be useful in the context of work or personal life when we need to negate the idea of setting up on something.