ξυλοκέφαλος
From LSJ
μηδὲν κοτυλίζειν, ἀλλὰ καταπάττειν χύδην → not to sell by the cupful, but to dole out indiscriminately | not to sell by retail but wholesale
Greek Monolingual
-η, -ο
(υβριστικά) αυτός που δεν μαθαίνει εύκολα, ηλίθιος, ξεροκέφαλος.