Definitions

1. noun

A device that detects and indicates the presence of something, especially a gas or a vapor.

“The fire alarm is a sniffer that detects smoke in the building.”

2. noun

A person who sniffs or has a keen sense of smell, often in a contemptuous or disdainful manner.

“The sniffer caught the whiff of the rotten food from across the room.”

3. verb

To search for or try to find something, especially a computer virus or a hidden file.

“The hacker tried to sniffer the network to find the hidden malware.”