ὠφελήσιμος
From LSJ
οἵτινες πόλιν μίαν λαβόντες εὐρυπρωκτότεροι πολύ τῆς πόλεος ἀπεχώρησαν ἧς εἷλον τότε → after taking a single city they returned home, with arses much wider than the city they captured
English (LSJ)
ον,
A useful, serviceable, profitable, πολλοὶ μὲν ἐχθροί, παῦρα δ' ὠ. S.Aj.1022; ὠ. [λόγος] Ar.Av.317 (troch.).