ἀβαρβάριστος

ον, Adv.
A. without barbarisms, Lex.Vind. 294. Adv. ‐τως EM 331.37. ἀβάρβαρος, f.l. for ἀβόρβορος, q.v.
Liddell, Scott & Jones
A Greek-English Lexicon, 1940
An open-access project