errant
adj.adj. describing something that is moving away from a path or a set of rules. It is an old-fashioned word that you might see in stories about knights or old laws.
adj. deviating from a proper course, path, or set of rules. Often used in legal or historical contexts to describe actions that are unlawful or morally wrong.
The knight was punished for his errant behavior.
The judge dismissed the case because the evidence was based on an errant assumption about the defendant's whereabouts.
The novel explores the consequences of an errant knight who, driven by personal ambition, violates the sacred oaths of his order and brings ruin to his kingdom.
From Middle English erraunt [and other forms], from Anglo-Norman erraunt, from Old French errant, the present participle of errer (“to walk (to); to wander (to); (figuratively) to travel, voyage”), and then: from Vulgar Latin iterāre (compare Late Latin itinerāre, itinerāri (“to travel, voyage”)), from Latin iter (“a route (including a journey, trip; a course; a path; a road)”), ultimately from Proto-Indo-European h₁ey- (“to go”); and from Latin errantem, the accusative feminine or masculine singular of errāns (“straying, errant; wandering”), the present active participle of errō (“to rove, wander; to get lost, go astray; to err, wander from the truth”), ultimately from Proto-Indo-European h₁ers- (“to flow”). Doublet of arrant.