ὠφελητικός
From LSJ
Ὤδινεν ὄρος, Ζεὺς δ' ἐφοβεῖτο, τὸ δ' ἔτεκεν μῦν → The mountain was in labor—even Zeus was afraid—but gave birth to a mouse
English (LSJ)
ή, όν,
A helpful, useful, Ph.1.14, Fr.55 H., Arr. Epict.2.10.23, Aristid.Quint.2.9, Dam.Isid.296.
Greek (Liddell-Scott)
ὠφελητικός: -ή, -όν, βοηθητικός, χρήσιμος, Φίλων 1. 120.