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Characteristic of mental derangement: mad laughter. Temporarily or apparently deranged by violent sensations, emotions, or ideas: was mad with jealousy. I was mad to have hired her in the first place. Feeling or showing strong liking or enthusiasm: mad about sports. Marked by a lack of restraint, especially by extreme excitement, confusion, or agitation: a mad scramble for the bus. Exhibiting uncharacteristic aggressiveness, especially as a result of rabies, spongiform encephalopathy, or another neurological disease. It’s really mad that they can come.

Dictionary of the English Language, Fifth Edition. 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. Because this sense is sometimes criticized, mad is often replaced byangryin formal contexts:The president is angry at Congress for overriding his veto. Copyright 2005, 1997, 1991 by Random House, Inc. A very strong wind, probably related to Old Norse galinn, “frantic, mad. Refers to the fact that hat makers suffered mental illness in the old days when they got mercury poisoning from treating fur.