when you breathe in air noisily through your nose, for example in order to smell something, because you have a cold, or in order to show your disapproval:
a sniff of disapproval
She gave a loud sniff.
2 British English informal
a small amount or sign of something [= hint]
3 British English informal
to examine a place carefully
4 British English informal
to not have any chance of getting something or being successful:
He never even got a sniff of the target.