What is the latin for the word Peaceful?

There are two options here:

Taceo, ere means to be silent. Imperative: Tace (you, be silent). Tacete (y'all, be silent).

Quiesco, ere means to be quiet. Imperative: Quiesce (you, be quiet). Quiescete (y'all be quiet).

Quiesco is more polite than taceo.