We say: "Vigilante" is a Spanish word meaning "guard". - presumably as a noun.
It's kind of news to me. In modern peninsular Spanish ,"vigilar" is "watch" or "keep an eye on". "Vigilado" could be the person who is watched. But, as far as I am aware the English word, "guard" (as a noun) is "guardia" in Spanish. Though I can see there may well be an original root word for "vigilante" there.