A wildcat is any small or medium-sized wild cat that isn't a lion, tiger, leopard, or other big cat. Bobcats, lynxes, ocelots, and the African wildcat (ancestor of house cats) are all wildcats. These fierce hunters live on every continent except Australia and Antarctica, prowling forests, deserts, and mountains. While they look somewhat like house cats, wildcats are untamed animals that hunt for survival and avoid humans.

The word also describes something risky, unauthorized, or operating outside normal rules. A wildcat strike happens when workers walk off the job without their union's official approval, acting on their own. Wildcat drilling refers to searching for oil in areas where no one has found it before, a gamble that might pay off spectacularly or fail completely. In 19th-century America, poorly regulated banks were called wildcat banks and often collapsed, leaving people's savings worthless.

The sports world uses wildcat too. Some teams adopt wildcats as fierce mascots. In football, the wildcat formation tricks opponents by having someone other than the quarterback take the snap directly, keeping defenses guessing. Like the animal itself, anything called wildcat suggests unpredictability, independence, and a willingness to take chances.