Antonyms for the term "comes on board" may include "steps down," "bows out," "refuses to participate," "disengages," and "withdraws." These words indicate a lack of commitment or activity towards a project or endeavor. Alternatively, antonyms for "comes on board" could be terms like "abstains," "resigns," "backs out," or "sits out," which indicate a conscious decision to distance oneself from an initiative or organization. These words may apply to situations where an individual or group chooses not to support a particular venture, often due to ethical or personal reasons. In any case, understanding antonyms for "comes on board" can help individuals express a range of attitudes towards particular projects or initiatives.