Outside smell: the slightly musty, earthy odor that sticks to your body after being outside. It is said to be certain pollutants traveling in the air that give you the "outside smell". Some people really detest the smell and some would call it mild but noticeable.
Person 1: you smell strange, where have you been?
Person 2: well I ran to the convenience store and chilled at the park for a few minutes.
Person 1: Oh, you have the outside smell.
A New York City catchphrase popularized by Sidetalk (@sidetalknyc) that refers to being outside, staying active, and making moves, rather than sitting inside and doing nothing.