1. The act of questioning the viability of an idea or course of action. Josh thinks he has a solid plan, but it doesn't pass the sniff test for me—I don't see how it will be profitable.

2. In medicine, a test of the phrenic nerve in which the patient must sniff forcefully. Next, we're going to do a sniff test so that I can see exactly how your phrenic nerve is functioning.

3. In medicine, a way to recognize bacterial vaginosis (which presents with a fishlike odor). I've only done a sniff test so far, but I think that patient has bacterial vaginosis.

4. The act of smelling something to determine whether or not it has a fresh odor. These leftovers pass the sniff test, so I'll heat them up for lunch. You can't wear that shirt again without washing it—it definitely doesn't pass the sniff test!