If you describe something as maddening, you mean that it makes you feel angry, irritated, or frustrated. Shopping in the January sales can be maddening = infuriating + maddeningly mad·den·ing·ly The service is maddeningly slow. very annoying = infuriating
extremely annoying or displeasing; "his cavelier curtness of manner was exasperating"; "I've had an exasperating day"; "her infuriating indifference"; "the ceaseless tumult of the jukebox was maddening"
To madden a person or animal means to make them very angry. He knew that what he was saying did not reach her. And the knowledge of it maddened him = infuriate. to make someone very angry or annoyed