An Etymological Dictionary of the German Language/Wolf
Wolf, m., ‘wolf,’ from the equiv. MidHG. and OHG. wolf, m.; common to Teut. and also to Aryan; comp. Goth. wulfs, OSax. wulf, Du. wolf, AS. wulf, E. wolf. Teut. wulfo-, from wulpo-, is based on Aryan wlqo-, wlko-; comp. Sans. vṛ́ka, OSlov. vlûkŭ. Lith. vilkas, Gr. λύκος, Lat. lupus, ‘wolf.’ On account of this apparent similarity between Wolf and the equiv. words of the other Aryan languages, Lat. vulpes, ‘fox,’ cannot be allied. The Aryan term wlko- has been rightly compared with the Aryan root welk, ‘to march,’ preserved in Gr. ἕλκω, OSlov. vlęką, so that Wolf meant perhaps ‘robber.’ The word was often used in Teut. to form names of persons; comp. Wolfram, under Rabe; Rudolf, from Ruodolf (lit. ‘famous wolf,’ see Ruhm), Adolf, from Adalolf (lit. ‘noble wolf, see Adel).