straggler

Someone who goes against the direct or proper course, or from the company to which they belong.

One who falls behind the rest, for example in a race.

落伍者

One who roams without any settled direction.

游荡者

A migratory animal found away from its usual range.

A roving vagabond.

Something that shoots, or spreads out, beyond the rest, or too far; an exuberant growth.

Something that stands alone or by itself.