If the key to a word’s meaning is its etymology, then pacifier and peacemaker should mean exactly the same thing.
Paci- means “peace.” “Fier” means “maker.” Both are from Latin (pax and facere,* respectively).
But as I always say, it’s very important never to confuse what you put in your baby’s mouth with what you send to conflict-ridden regions of the globe.
A word’s etymology may be helpful if we don’t have better clues to its meaning. But all words, like sheep, have gone astray from their roots. And that’s okay. Really. You couldn’t use words in a way matching their etymologies even if you tried. First off, you don’t know the histories of most of the words you use. No one does. Second, no one else would understand you. Third, how could you use old words for new things? Computer, for example. Or even new combinations like air conditioner.