A sniffer is a person or animal with a keen sense of smell, often used to detect and identify scents that are imperceptible to the average nose. This term can also refer to a device or software that is designed to intercept and analyze data packets on a network, allowing for the detection of potential security threats or network issues. In both cases, a sniffer is able to pick up on subtle or hidden scents or signals, making it a valuable tool for various purposes such as tracking, security, and troubleshooting.