πολυωφελής

ές, Adv.

ὄφελος

A. very useful, Arist. EN 1095a11, D.H. 1.36, etc.: Comp., SIG 1164 (Dodona, iv/iii B.C.): Sup., λογισμός Ael. NAPraef. Adv. ‐λῶς, τῇ πόλει Ar. Th. 304: Sup. ‐έστατα X. Eq.Mag. 1.1.
Liddell, Scott & Jones
A Greek-English Lexicon, 1940
An open-access project