Idiosyncrasy refers to a unique characteristic or behavior that is specific to an individual. It can be a quirky habit, a particular way of thinking, or a distinctive preference that sets someone apart from others. For example, a person might have an idiosyncrasy of always wearing mismatched socks or eating dessert before dinner. These traits often make individuals more interesting and memorable. In psychology, idiosyncrasies can also relate to how people respond to certain situations or stimuli. For instance, someone might have an idiosyncratic reaction to caffeine, feeling overly energetic while others feel jittery. Understanding these unique traits can help in appreciating the diversity of human behavior.