This etymology accounts for the meaning "bad" through a verb of motion, χάζομαι "to retreat, to flee". From the formal point of view, it relies on the alternation between aspirate stop and plain voiceless stop, which was familiar to Greek scholars because of the many cases where aspirate dissimilation (Grassmann's law) occurs, as in reduplicated forms like κέχρημαι or pairs like τρέφω / θρέψω. In Greek scholarly literature, the dissimilation rule is said to be a consequence of ἐπαλληλία τῶν δασέων "succession of aspirate consonants": however, the derivation of κακός from χάζομαι is not a case of aspiration dissimilation since there is only one aspirate consonant in the assumed etymon *χακός; we are dealing here with an extension of the rule, involving deaspiration of the first consonant as in true cases of aspiration dissimilation. From the semantic point of view, it distinguishes two cases and plays on the diathesis, κακός is either the coward, the one who flees (active), or the bad person, away from whom others have to flee (passive). It is likely that the explanation involving the active meaning, which accounts for only one meaning of κακός, is older, and that the explanation involving the passive meaning was developed by twisting the former in order to adapt it to the more general meaning "bad"