Etymology
From Middle English warloghe, warlowe, warloȝe, from Old English wǣrloga (“traitor, deceiver”, literally “truce-breaker”), from Proto-West Germanic *wārulogō (“liar”), equivalent to Old English wǣr (“covenant, truce, pact, promise”) (from Proto-Indo-European *weh₁- (“true”); whence also Latin vērus) + loga (“liar”), from Proto-Germanic *lugô, related to Old English lēogan (whence English lie). The hard -ck ending originated in Scottish and Northern English, like the sense "male magic-user" (from the notion that such men were in league with the Devil and had thus broken their baptismal vows / betrayed Christianity). Cognate with Old Saxon wārlogo (“liar, unfaithful or insidious one”).
A few writers alternatively propose a derivation from Old Norse varðlokkur (“incantations, charms”, literal