Mad/mæd/ Definition 1 of 4Pro Tip 1/3Emotional Intensity Use 'mad' to express a strong emotional response, not just slight annoyance. He was mad with anger when the package was lost. Pro Tip 2/3Informal Situations 'Mad' is commonly used in casual or informal conversations rather than formal ones. I can’t believe you did that, I’m so mad right now! Pro Tip 3/3Gradable Intensity 'Mad' can be intensified by adding words like 'really' or 'extremely'. She was really mad about the decision.