Asumphonos (ἀσύμφωνος) means "out of harmony," "discordant," "not in agreement." It is the opposite of sumphonos (harmonious, "symphony"). It appears only once in the New Testament (Acts 28:25), describing the state of Paul's accusers as they departed from his Roman lodging — they left disagreeing among themselves.
The final image of Paul's Jewish accusers in Acts is one of asumphonos — dissonance. They could not agree on what to make of Paul's message. This discord is the tragic foil to the harmony the gospel creates: "May the God who gives endurance and encouragement give you the same attitude of mind toward each other that Christ Jesus had, so that with one mind and one voice you may glorify the God and Father of our Lord Jesus Christ" (Romans 15:5–6). The gospel is symphonic — it calls broken, discordant people into one harmonious chorus. Rejection of the gospel leaves people in the dissonance they started with. Agreement with the truth of Christ is the only path to deep, lasting harmony between human beings.