To differ; be not the same or alike; be variant; not to accord or harmonize: as, two ideas or two statements disagree when they are not substantially identical, or when they are not exactly alike; the witnesses disagree.To differ in opinion; be at variance; express contrary views: as, the best judges sometimes disagree.To be in a state of discord or altercation; wrangle; quarrel.To conflict in action or effect; be incompatible or unsuitable: as, food that disagrees with the stomach.