Antonyms for the phrase "say amen to" would include "disagree with," "oppose," "reject," "refuse," or "deny." To say "amen" to something is to express agreement or affirmation, so antonyms would refer to the opposite, indicating disagreement or resistance. Other possible antonyms might include "disbelieve," "doubt," "question," "contest," or "challenge," depending on the nuances of the context and the speaker's intent. Using antonyms to "say amen to" can help to convey a range of conflicting attitudes, opinions, or beliefs, highlighting the complexities and contradictions of human communication and interaction.