The verb κατοφρυόομαι (of which the headword, evidently extracted from somewhere, is the perfect infinitive) is late, and usually takes ἐπί or the accusative for the thing to be stern about. However, it takes the genitive (cf. kappa 1102) in its first appearance, in Acta Andreae 50 (C2 CE); cf. John of Damascus, Sacra parallela Rupefucaldina, MPG 96.460.44 (C8 CE), Antonius III Studites, Oratio p. 116 (C10 CE), and Michael Psellus, Historia Brevis 46.13 (C11 CE). See the LSJ entry at web address 1.