1a person who sniffs, especially one who sniffs a drug or toxic substance: [with adjective]:a glue sniffer
informal a device for detecting an invisible and dangerous substance, such as gas or radiation:electronic sniffers are used to detect the presence of a nuclear mass
2 informal a person’s nose.
3 (also sniffer program) trademark a computer program that detects and records a variety of restricted information, especially the secret passwords needed to gain access to files or networks.
