[noun] [C]My cousin is a glue sniffer (= a person who takes in the gas from glue because of the pleasurable feelings that that gives).A sniffer dog is a dog that is trained and used by the police or army to find hidden drugs and bombs by smelling them.
SNIFFER
Meaning of SNIFFER in English
Cambridge English vocab. Кембриджский английский словарь. 2012