stray

an animal that has strayed (especially a domestic animal)

move about aimlessly or without any destination, often in search of food or employment; "The gypsies roamed the woods"; "roving vagabonds"; "the wandering Jew"; "The cattle roam across the prairie"; "the laborers drift from one town to the next"; "They rolled from town to town"

wander from a direct course or at random; "The child strayed from the path and her parents lost sight of her"; "don't drift from the set course"

lose clarity or turn aside especially from the main subject of attention or course of argument in writing, thinking, or speaking; "She always digresses when telling a story"; "her mind wanders"; "Don't digress when you give a lecture"

not close together in time; "isolated instances of rebellion"; "a few stray crumbs"

(of an animal) having no home or having wandered away from home; "a stray calf"; "a stray dog"