εὐτονία
From LSJ
Δεῖ τοὺς μὲν εἶναι δυστυχεῖς, τοὺς δ' εὐτυχεῖς → Aliis necesse est bene sit, aliis sit male → Die einen trifft das Unglück, andere das Glück
English (LSJ)
ἡ,
A tension, vigour, D.S.5.39; σκελῶν ib.34: esp. in Stoic philos. (cf. τόνος), Chrysipp.Stoic.2.146, etc.; ὁ ἐν τῇ ψυχῇ τόνος λέγεται ὡς εὐ. καὶ ἀτονία ib. 3.123, cf. Phld.Ir.p.69 W.; εὐ. ψυχῆς, of courage, Stoic.3.66, cf. 73: generally, vigour of character, Plu.Phoc.3, 2.456f, BGU786ii 1 (ii A.D.); also, vigour of style, D.H.Vett.Cens.2.3, Hermog.Id.1.11, Aps.p.282 H. b Medic., tension, Ruf.Sat.Gon.46 (pl.); also μαλθακὴ εὐ. gentle force, Hp.Ep.15. c elasticity, Ph.Bel.71.33.
