From Wikipedia:
Because of the obscurity of the name “Perseus” and the legendary character of its bearer, most etymologists presume that it might be pre-Greek; however, the name of Perseus’s native city was Greek and so were the names of his wife and relatives. There is some idea that it descended into Greek from the Proto-Indo-European language. In that regard Robert Graves has proposed the only Greek derivation available. Perseus might be from the Greek verb πέρθειν (pérthein, “to waste, ravage, sack, destroy”) some form of which appears in Homeric epithets. According to Carl Darling Buck (Comparative Grammar of Greek and Latin), the –eus suffix is typically used to form an agent noun, in this case from the aorist stem, pers-. Pers-eus therefore is a “sacker of cities”, that is, a soldier by occupation, a fitting name for the first Mycenaean warrior.
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