irenic
Promoting or fitted to promote peace or peacemaking, especially over disputes; conciliatory, non-confrontational, peaceful.
Plato and the Athenians must have felt almost as uncomfortable with Xenophon's irenic intervention as one feels at times in an argument when—just as the point in dispute, precisely by being brought to a head, begins to be interesting—a helpful third party kindly takes it upon himself to reconcile the disputants, to take the whole matter back to a triviality
Where it comes from
From Ancient Greek εἰρηνικός (eirēnikós, “characterized by peace, peaceful”) + English -ic (suffix forming adjectives with the sense ‘of or pertaining to’). Εἰρηνικός (Eirēnikós) is derived from εἰρήνη (eirḗnē, “peace”) (possibly from εἴρω (eírō, “to fasten together”) (ultimately from Proto-Indo-European *ser- (“(verb) to bind, tie together; (noun) thread”)), or εἴρω (eírō, “to say, speak”) (ultimately from Proto-Indo-European *werh₁- (“to say, speak”))) + -ῐκός (-ĭkós, suffix forming adjectives with the sense ‘of or pertaining to’).
Adapted from the Wiktionary entry irenic (CC BY-SA 4.0).