Outside Dog
An outside dog refers to a person who exhibits behavior of having lived, usually for a number of years, outside. This term usually refers to tramps, vagrants or the homeless. Some of these behaviors might include being a loner, wearing more clothes than others might, evading public scrutiny, sleeping on the floor rather than in a bed or being disheveled or unshaven.
“That wool coat is a dead give-away that he’s an outside dog.”