aberrant (adj.)

"wandering from the usual course," 1798, originally in natural history, "differing somewhat from a group in which it is placed," from Latin aberrantem (nominative aberrans), present participle of aberrare "to wander away, go astray," literally and figuratively, from ab "off, away from" (see ab-) + errare "to wander, stray, roam, rove" (see err). Related: Aberrance; aberrancy (1660s). The verb aberrate is rare.