late 14c., from Latin catoblepas, from Greek katobleps, from kato "downward" (related to kata-) + blepein "to look," but this might be ancient folk etymology. Name given by ancient authors to some African animal.
A wylde beest that hyghte Catoblefas and hath a lytyll body and nyce in all membres and a grete heed hangynge alway to-warde the erth. [John of Trevisa, translation of Bartholomew de Glanville's "De proprietatibus rerum," 1398]