We don't have synonyms for eirenic yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are irenic and sirenic.
(adj) :
Alternative spelling of irenic. [(chiefly theology) Promoting or fitted to promote peace or peacemaking, especially over disputes; conciliatory, non-confrontational, peaceful.]
(adj) :
Alternative spelling of irenic. [(chiefly theology) Promoting or fitted to promote peace or peacemaking, especially over disputes; conciliatory, non-confrontational, peaceful.]