Sniff/snɪf/ Definition 1 of 5Pro Tip 1/3Animals Investigate Animals often 'sniff' to explore their environment or track scents. A bear sniffed the air, catching the smell of food. Pro Tip 2/3Sensory Experience 'Sniff' indicates voluntary smelling, commonly to assess an odour. She sniffed the perfume on her wrist. Pro Tip 3/3Subtle Suspicion Metaphorically used to describe someone becoming subtly aware of something. He sniffed trouble brewing at the meeting.