From Longman Dictionary of Contemporary Englishsniff something ↔ out phrasal verb1 SMELLto discover or find something by its smell A customs officer came round with a dog to sniff out drugs.2 informalFIND OUT to find out or discover something Vic’s been trying to sniff out where you went last night. → sniff→ See Verb table
Examples from the Corpus
sniff out• There are an awful lot of opportunities around if you can only sniff them out.• He knew the local C.I.D. and it was said he could sniff a copper out a mile away.• Like animals, they sniff me out, like dogs.• In trials with real and willing patients, it looks as if George sniffed right five out of seven times.• They had found him quicker than he'd anticipated, sniffing him out through the darkened streets. 