IPA: /ˈsnɪfər/
KK: /ˈsnɪfər/
A device or person that detects or monitors something, often used to capture data or information, especially in the context of network traffic or illicit activities.
The network sniffer captured all the data packets being transmitted over the internet.
Sniffer → The word is formed from "sniff" (of uncertain origin, possibly imitative of the sound made when inhaling) and the suffix "-er" (meaning a person who performs an action). A sniffer is a person or device that performs the action of sniffing, typically to detect or identify something by smell.
Think of someone who 'sniffs' to detect scents — the '-er' indicates that this person is actively doing the action of sniffing.