Errant is an adjective that means “deviating from the regular or proper course”, “roving, especially in search of adventure”, or “aimless”.
From the Online Etymology Dictionary:
1335, from Anglo-Fr. erraunt, from two O.Fr. words that were confused even before they reached Eng.: 1. O.Fr. errant, prp. of errer "to travel or wander," from L.L. iterare, from L. iter "journey, way," from root of ire "to go" (see ion); 2. O.Fr. errant, pp. of errer (see err). Much of the sense of the latter has gone with Eng. arrant (q.v.).
Looking at usage examples, I see people writing about errant winds, errant knights, errant cattle, errant teenagers… I’d say errant is a pretty easy word to fit into daily conversation.