πονηρεύομαι
From LSJ
Ὁ συκοφάντης ἐστὶν ἐν πόλει λύκος (τοῖς πέλας λύκος) → Calumniator, quemquem novit, huic lupus'st → Der Denunziant lebt in der Stadt gleichsam als Wolf (ist seinen Nachbarn wie ein Wolf)
English (LSJ)
A to be in a bad state, Hp.Coac.194; πονηρευόμενα ἕλκη malignant ulcers, Dsc.1.106, cf. Ruf. ap. Orib.45.30.31. II act wickedly, play the knave, Heraclit.125a, Arist.Rh.1411a17, Men. Epit.133; οἱ πεπονηρευμένοι D.19.32, cf. Phld.Rh.1.43 S., Plu.Cat.Ma. 9, etc.: c. dat., towards or against . ., Thd.Su.61: with Preps., ἐν τοῖς προφήταις LXX 1 Ch.16.22; κατ' ἐμοῦ Thd.Su.43: also c. acc., τινα LXX Ec.7.22(23); intend maliciously, c. inf., ib.De.19.19; τοῦ ἀποκτεῖναί τινα ib.Ge.37.18, al.