rover

noun

a) (usually plural) A randomly selected target.

1890 "By my hilt! no. There was little Robby Withstaff, and Andrew Salblaster, and Wat Alspaye, who broke the neck of the German. Mon Dieu! what men they were! Take them how you would, at long butts or short, hoyles, rounds, or rovers, better bowmen never twirled a shaft over their thumb-nails." — Arthur Conan Doyle, The White Company, [ Chapter 22.]

b) One who roves.

1846 But these islands, undisturbed for years, relapsed into their previous obscurity; and it is only recently that anything has been known concerning them. Once in the course of a half century, to be sure, some adventurous rover would break in upon their peaceful repose. and astonished at the unusual scene, would be almost tempted to claim the merit of a new discovery. — Herman Melville, Typee, [ Chapter 1.]