Saying amen to means to agree or affirm a statement, prayer or religious oath. However, there are several antonyms for this phrase which convey a sense of disagreement, disapproval or dissent. Some of these antonyms include denying, rejecting, contradicting, disagreeing, repudiating, refuting, opposing, and contesting. These words can be used in situations where one disagrees with a statement or idea and wishes to express their dissent. Therefore, while saying amen to conveys a sense of agreement, the antonyms for this phrase convey moments of disagreement, and can be useful in communicating dissent.