A monkey is a type of intelligent, agile animal that lives mostly in tropical forests around the world. Most monkeys have long tails they use for balance or even gripping branches, hands and feet designed for climbing, and expressive faces that show what they're feeling. They live in social groups, communicate with each other through sounds and gestures, and spend much of their time in trees searching for fruits, leaves, and insects to eat.

There are hundreds of monkey species, from tiny pygmy marmosets that fit in your hand to large baboons that walk on the ground. Spider monkeys swing gracefully through South American rainforests, while macaques in Asia have learned to live near humans, sometimes becoming mischievous visitors in towns and temples. Monkeys are close relatives of apes (like gorillas and chimpanzees), but most monkeys have tails while apes don't.

As a verb, monkey means to fool around or play in a silly way. When someone says “stop monkeying around,” they mean stop fooling around and get serious. This comes from watching how playful and energetic real monkeys are, always climbing, jumping, and causing cheerful chaos in their forest homes.