This verb appears once in Homer (Iliad 21.347, in a simile comparing the drying, under Hephaistos' fire, of the plain which the river Skamandros had flooded, to the drying of a recently soaked ἀλωή (here probably "cultivated plot", less likely "threshing-floor") by a north wind - whereat "he who εθείρῃ it" rejoices.
The verb has no agreed etymology, but the context requires a meaning like "tend" or "till"; the cultivator's satisfaction would be concurred in by the chorus of Aristophanes' Wasps (264-5: "the crops that don't ripen early need rain to fall and then a north wind to blow on them"). Ancient scholars evidently did not know what ἐθείρῃ meant, but were mostly convinced that it was derived from ἔθος ("habit") or from the rare participle ἔθων , "habitually, persistently" (Iliad 9.540, 16.260) and offered glosses similar to the Suda's (with the exception of Hesychios who glosses "thinks worthy of being cared for").
For care exercised "habitually" see already epsilon 319; and for "habitually cf. epsilon 329, epsilon 2592, pi 551.