Irrational behavior refers to actions or decisions that are not based on reason or sound judgment. It may be characterized by emotions or other psychological factors that influence decision-making, rather than logical or evidence-based thinking. Irrational behavior can sometimes lead to outcomes that are not in an individual's best interests, or that are harmful to others.

Examples of irrational behavior might include making impulsive decisions, engaging in risky behavior, or failing to consider the long-term consequences of one's actions. In some cases, irrational behavior may be a result of mental health issues or other underlying psychological conditions.