sniff
v. B1 Intermediate US //ˈsnɪf// UK //snˈɪf// sniff
v. to breathe in quickly through your nose, usually to smell something or because you have a cold. You might do this if you are trying not to cry.
v. to inhale audibly through the nose, often to perceive an odor or to clear the nasal passages. Frequently used to describe the physical reaction to minor illness or suppressed emotion.
The dog began to sniff the grass for a scent.
She tried to hide her sadness, but a small sniff gave her away to her friends.
The detective leaned down to sniff the air, hoping to catch a trace of the expensive perfume mentioned in the witness report.
From Middle English sniffen, of imitative origin.
Usage
The verb can be used both transitively ('sniff the flower') and intransitively ('he sniffed loudly').