Abarim Publications' online Biblical Greek Dictionary
αρι αρετη αριστευω
The common and inseparable prefix αρι (ari) — also occurring as ερι (eri) — is used to strengthen the meaning of a word. It often can be translated by 'very much' or constructions to that extent: αριδακρυς (aridakrus) means very tearful; αριφρων (ariphron) means very wise; αριηκοος (ariekoos) means much heard of.
Our prefix αρι (ari) shares the root with the unbiblical name Ares (a word which originally denoted virtue in war; a quality that was later deified as the destroying and slaughtering son of Zeus and Hera and which in Latin is called Mars) and the noun αρετη (arete), which denotes excellence:
In older texts, the feminine noun αρετη (arete) appears to have denoted excellence of any kind but mostly of manly qualities (comparable to the Latin word virtus). Plato used it to convey moral excellence and virtue, and later authors ascribed the plural of αρετη (arete) to gods, in the meaning of glorious deeds, wonders, miracles.
In the New Testament it occurs three times, twice in the epistles of Peter. In 1 Peter 2:9 it occurs in plural and is commonly translated with excellencies or praises. In 2 Peter 1:5 it's commonly translated with moral excellence or virtue. On this occasion it appears juxtaposed with δοξα (doxa), meaning glory or excellent reputation.
Paul uses this word in Philippians 4:8, where he writes, "Finally, brethren, whatever is true, whatever is honorable, whatever is right, whatever is pure, whatever is lovely, whatever is of good repute, if there is any excellence and if anything worthy of praise, let your mind dwell on these things."
Doubtlessly connected to the above is the verb αριστευω (aristeuo), meaning to be the best or bravest. This verb is not actually used in the Bible (apart from its contribution to a few names) but in the classics it may refer to people being the best at a certain activity (such as fighting) or of items such as fruits or lands as being of a superior quality. In English this verb survives in the word aristocracy.