To draw air quickly through the nose to smell.

To say something while sniffing from tears, illness, or disdain.

To pry or investigate intrusively; sniff around or into.

To show contempt for; to sniff at something.

Computing: To intercept and analyze network traffic packets.

A short sniff or instance of sniffing.

A very small amount or faint sign.

The sound of a short, audible inhalation.