sophrosyne
The Ancient Greek concept of an ideal of excellence of character and soundness of mind, which when combined in one well-balanced individual leads to other qualities, such as temperance, moderation, prudence, and self-control.
uncountable
With them the gods were confederated to break barbarian arrogance. Nation and individual citizen, then as now, must reverence sophrosyne.
Where it comes from
From Ancient Greek σωφροσύνη (sōphrosúnē, “soundness of mind, prudence, temperance”) from σώφρων (sṓphrōn, “sane, moderate, prudent”) (from σῶς (sôs, “safe, sound, whole”) + φρήν (phrḗn, “mind”)) + -σύνη (-súnē, abstract noun suffix).
Adapted from the Wiktionary entry sophrosyne (CC BY-SA 4.0).