Pacific, peaceable, peaceful, irenic, pacifist, pacifistic are sometimes confused because they all involve the idea of affording or promoting peace.
But pacific applies chiefly to persons or to utterances, acts, influences, or ideas that tend to make peace or to conciliate strife.
Peaceable also applies to persons or to their actions or words, but it describes their character or quality as peace- loving, as disposed to avoid strife, or as inclined to keep peace, rather than their aims or tendencies.
Peaceful applies especially to a life, a condition or state, a period or age, or a country or people in which peace prevails or there is no strife, but it may apply to whatever is indicative of peace, especially of mind, or provides an opportunity for such peace.
Irenic, which applies primarily to peace in connection with religious controversy, may describe attitudes and measures likely to allay dispute.
Pacifist and pacifistic apply chiefly to the views, arguments, writings, or attitudes of opponents of war or the use of military force for any purpose but they may also apply to the spirit or utterances of someone who conscientiously objects to wars or who would substitute arbitration for conflict in the settlement of any disputes.