Antonyms for the phrase "swore on bible" are numerous and varied, depending on the context and purpose of the oath. Some antonyms could be "denied on oath," "refused to swear," "rejected under oath," "renounced under penalty of perjury," or "disavowed under legal penalty." Other antonyms may include "affirmed without an oath," "declared without a vow," "pledged without a warrant," or "asserted without a guarantee." In certain cases, the opposite of "swore on bible" might be simply "kept silent," "withheld comment," or "remained neutral." Ultimately, the choice of antonym would depend on the speaker's intention, credibility, and level of commitment to the truth.