Levelheadedness is the state of being calm, rational, and clear-headed. Its antonyms, or words that have the opposite meaning, include irrationality, impulsiveness, recklessness, and thoughtlessness. These words describe a lack of sound judgment and the inability to make logical decisions. They are often associated with hasty or emotional reactions to situations, without carefully considering the consequences. Another antonym might be hysteria, which suggests extreme emotional distress that can lead to irrational behavior. In contrast, levelheadedness implies a measured response to difficult situations, and the ability to stay calm and focused even under pressure.