From the same as arrhen; properly, manliness (valor), i.e. Excellence (intrinsic or attributed) -- praise, virtue.
see GREEK arrhen
1. a virtuous course of thought, feeling and action; virtue, moral goodness (Wis. 4:1 Wis. 5:13; often in 4 Macc. and in Greek writings): 2 Peter 1:5 (others take it here specifically, viz. moral vigor; cf. next entry).
2. any particular moral excellence, as modesty, purity; hence (plural αἱ ἀρεταί, Wis. 8:7; often in 4 Macc. and in the Greek philosophers) τίς ἀρετή, Philippians 4:8. Used of God, it denotes a. his power: 2 Peter 1:3.
b. in the plural his excellences, perfections, 'which shine forth in our gratuitous calling and in the whole work of our salvation' (John Gerhard): 1 Peter 2:9. (In the Sept. for הוד splendor, glory, Habakkuk 3:3, of God; Zechariah 6:13, of the Messiah; in plural for תְּהִלּות praises, of God, Isaiah 43:21; Isaiah 42:12; Isaiah 63:7.)