Errant

adj. straying, erring; roving, wandering, journeying; aimlessly moving from one place to another

A knight-errant (plural knights-errant) is a figure of medieval chivalric romance literature. "Errant" meaning wandering or roving, indicates how the knight-errant would typically wander the land in search of adventures to prove himself as a knight, such as in a pas d'Armes. The first known appearance of the term "knight-errant" was in the 14th century poem Sir Gawain and the Green Knight, where Sir Gawain arrives at the castle of Sir Bercilak de Haudesert after long journeys, and Sir Bercilak goes to welcome the "knygt erraunt."
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Adjective
1. straying from the right course or from accepted standards; "errant youngsters"
(similar) fallible
2. uncontrolled motion that is irregular or unpredictable; "an errant breeze"
(similar) uncontrolled

adj. wandering, vagrant, roaming; erratic, roving; vagabond, stray, excursive

n. wanderer, vagabond

v. wander, roam, rove, maunder, meander, range

(n.)
One who wanders about.
  

(a.)
Wandering; deviating from an appointed course, or from a direct path; roving.
  

(a.)
Notorious; notoriously bad; downright; arrant.
  

(a.)
Journeying; itinerant; -- formerly applied to judges who went on circuit and to bailiffs at large.