1sniff 
/ˈsnɪf/ verb
sniffs; sniffed; sniff·ing /ˈsnɪf/ verb 1 a [no obj] : to take air into your nose in short breaths that are loud enough to be heard
▪ She sniffed and wiped her nose with a tissue.
b : to smell (something or someone) by putting your nose close to it and taking air in through your nose in short breaths [+ obj] ▪ She put perfume on her wrist and sniffed it. ▪ The dog sniffed the carpet. [no obj] ▪ He held the flower up to his nose and sniffed. — often + at ▪ The cat sniffed at the food and walked away.
c [+ obj] : to take (something, such as fumes or a drug) into your body by inhaling it through your nose in order to get intoxicated
▪ sniffing glue/ether ▪ sniffing [=(more commonly) snorting] cocaine 2 a [+ obj] : to discover or find (something) by smelling — usually + out ▪ dogs that are trained to sniff out drugs — often used figuratively ▪ Several companies, sniffing [=sensing] profit potential, are investing in the area. ▪ My mother is an expert at sniffing out trouble. ▪ the ability to sniff out bargains ▪ By asking around, we were able to sniff out the truth.
b [no obj] : to search for something by smelling
▪ A dog sniffed (around) for drugs in the car. — often used figuratively ▪ The detective sniffed for clues. ▪ She has been sniffing (around/about) for a new job. 3 [+ obj] : to say (something) in a way that shows dislike, disapproval, etc.
▪ “I guess you don't need my help,” she sniffed.
▪ She sniffed and wiped her nose with a tissue.
b : to smell (something or someone) by putting your nose close to it and taking air in through your nose in short breaths [+ obj] ▪ She put perfume on her wrist and sniffed it. ▪ The dog sniffed the carpet. [no obj] ▪ He held the flower up to his nose and sniffed. — often + at ▪ The cat sniffed at the food and walked away.
c [+ obj] : to take (something, such as fumes or a drug) into your body by inhaling it through your nose in order to get intoxicated
▪ sniffing glue/ether ▪ sniffing [=(more commonly) snorting] cocaine
b [no obj] : to search for something by smelling
▪ A dog sniffed (around) for drugs in the car. — often used figuratively ▪ The detective sniffed for clues. ▪ She has been sniffing (around/about) for a new job.
▪ “I guess you don't need my help,” she sniffed.
sniff around/round [phrasal verb]
sniff around/round (someone) Brit, informal : to try to get (someone) as a romantic partner, employee, etc.
▪ His engagement hasn't stopped him from sniffing around other girls. ▪ Rival companies have been sniffing around her for years.
▪ His engagement hasn't stopped him from sniffing around other girls. ▪ Rival companies have been sniffing around her for years.
sniff at [phrasal verb]
sniff at (something) : to show dislike or disapproval of (something) especially because you think it is not important or worthy of respect
▪ Some people sniff at the idea of using fake flowers. ▪ It's not a big profit, but it's not to be sniffed at. = It's not a big profit, but it's nothing to sniff at.
▪ Some people sniff at the idea of using fake flowers. ▪ It's not a big profit, but it's not to be sniffed at. = It's not a big profit, but it's nothing to sniff at.
