The article argues that the Homeric compound ζαχρηής, which is usually understood as “strong, violent” and believed to be related to the aorist ἔχραε, belonging with Lat. in-gruo and Lith. griáuti, is in fact a possessive compound of the s-stem χρῆος (Hom. χρεῖος) “need, use, debt”, a derivative of χρή “necessity”. It is an Aeolic compound (ζα- < *δι̯α-) meaning “much needed, indispensable”. The meaning “violent, strong” arose from a reinterpretation in the context of Μ 346–347 and 359–360. With this new meaning, the word was reused as an epithet of winds in E 525 (ζαχρειῶν ἀνέμων “of violent winds”), and later on in Hellenistic poetry, thereby losing the original meaning. This has several implications: 1. the etymology of the group of ἔχραε is reexamined, and so is the derivational history of this group within Greek; 2. derivatives and compounds of χρή are reorganised; 3. the adverb ἀχρεῖον of the Homeric Vulgate is a thematicised form of the antonymic compound *ἀχρηής “needless”, and the meaning of Β 269 and σ 163 is reexamined accordingly; 4. Giangrande’s interpretation of Theocritus’ ζαχρεῖον (Id. 25, 6), as an adverb meaning “violently”, and not an adjective meaning “needy”, is confirmed; 5. the proposed correction ζαχρεῖ(α) in Aeschylus’ Suppl. 194, though widely accepted because of an erroneous interpretation of Theocritus’ ζαχρεῖον, must be rejected.