Old English hara "hare," from West Germanic *hasan- (cf. Old Frisian hasa, Middle Dutch haese, Dutch haas, Old High German haso, German Hase), possibly with a sense of "gray" (cf. Old English hasu, Old High German hasan "gray"), from PIE *kas- "gray" (cf. Latin canus "white, gray, gray-haired"). Perhaps cognate with Sanskrit sasah, Afghan soe, Welsh ceinach "hare." Rabbits burrow in the ground; hares do not. Hare-lip is from 1560s.
þou hast a crokyd tunge heldyng wyth hownd and wyth hare. ["Jacob's Well," c.1440]