The word evangelist was borrowed into English in the twelfth century CE, when it was spelled euangelist, ewangeliste, wangaliste, and evangaliste until evangelist became widely used in the eighteenth century. Before that, the word was spelled the same and had the same definition in Old French, and before that it showed up in Latin as evangelista. That in turn came from Ancient Greek euangelistes, which meant "bringer of good news" because it was composed out of the prefix eu-, meaning "good", and the verb angellein, meaning "to announce". Eu derives from Proto-Indo-European hsu, also "good", and angellein comes from angelos, which meant "messenger" and is the etymon of angel (with an uncertain origin, but there are cognates that suggest a possibly Semitic source).
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.