To Sniff

1. (transitive, intransitive) To make a short, audible inhalation, through the nose, as when smelling something.
2. To say something while sniffing, for example in case of illness or unhappiness, or in contempt.
3. (transitive) To perceive vaguely
4. To be dismissive or contemptuous of something.
5. (computing) To intercept and analyse packets of data being transmitted over a network.
6. (slang, Britain) To inhale drugs in powder form (usually cocaine) through the nose