Lewis & Short

Gordĭus, ii, m., = Γόρδιος, a king of Gordium, in Phrygia Major, famous for the inextricable knot on his chariot, which Alexander the Great cut with his sword, Curt. 3, 1, 15 sqq.; Just. 11, 7, 13 sqq.
Hence, Gordĭus, a, um, adj., of or belonging to Gordius: nodus, i. e. an insoluble problem, Amm. 14, 11, 1.