sniffer
nounUK /ˈsnɪf.ər/
US /ˈsnɪf.ɚ/
A sniffer is a person or thing that smells things.
The dog is a good sniffer and can find treats hidden in the house.
OTHER MEANINGS
2. A computer program or device that secretly watches information moving through a network.
The technician used a sniffer to check the network for problems.
3. A person who secretly looks for private information about others.
The office sniffer was always reading papers on other people's desks.
4. A small tube or device used to take quick breaths of something, such as medicine.
He used a sniffer to breathe in the medicine.