γελᾷ δ' ὁ μωρός, κἄν τι μὴ γέλοιον ᾖ → the fool laughs even when there's nothing to laugh at
turpīdo: ĭnis, f. contr. from turpidudo,I baseness, etc., Tert. Cor. Mil. 14; Cic. Rep. 1, 2, 2 MSS. (B. and K. turpitudinis; cf. Osann ad loc.).
turpīdō, ĭnis, f., c. turpedo : Aug. Serm. 120, 13.