Definition of "rover"

"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.

1890, Arthur Conan Doyle, chapter 22, in The White Company‎

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.

1846, Herman Melville, chapter 1, in Typee‎

I must go down to the seas again, to the vagrant gypsy life,To the gull's way and the whale's way, where the wind's like a whetted knife;And all I ask is a merry yarn from a laughing fellow-rover,And quiet sleep and a sweet dream when the long trick's over.

1902, John Masefield, Sea Fever

Give him the word, that I'm not a rover, and tell him that his lonely days are over.

1954, Pat Ballard (lyrics and music), “Mr. Sandman”

NASA's Mars Exploration Rover Opportunity is currently traveling southward over a pavement of outcrop dubbed the "Erebus Highway." "Erebus Crater," the rover's next target, lies less than 100 meters (328 feet) south of its current position

September 19, 2005, Dave Lane, Mars Exploration Rover "OPPORTUNITY"

I went to Coach Beamer and, because we had a lot of outside linebackers, ask him if I could play rover.

2011, Frank Beamer, Always a Hokie: Players, Coaches, and Fans Share Their Passion for Virginia Tech Football‎

All sorts, flights, rovers, and butt shafts.

1600 (first performance), Benjamin Jonson [i.e., Ben Jonson], “Cynthias Revels, or The Fountayne of Selfe-Loue. […]”, in The Workes of Ben Jonson (First Folio), London: […] Will[iam] Stansby, published 1616

Diogenes will deſpiſe thee for all that, who being expoſed and offered to ſale by the rovers and theeves that tooke him, cried and proclaimed himſelfe aloud: Who will buy a maſter who?

1603, Plutarch, “That Vice Alone is Sufficient to Make a Man Wretched”, in Philemon Holland, transl., The Philosophie, Commonlie Called, The Morals […], London: […] Arnold Hatfield, page 299

The first was this: our ship making her course towards the Canary Islands, or rather between those islands and the African shore, was surprised in the grey of the morning by a Turkish rover of Sallee, who gave chase to us with all the sail she could make.

1719 May 6 (Gregorian calendar), [Daniel Defoe], The Life and Strange Surprizing Adventures of Robinson Crusoe, […], 3rd edition, London: […] W[illiam] Taylor […], published 1719