I'm trying to write out an document of sorts though I need the word for "someone who warns". I've done a bit of searching but couldn't find anything.
I initially thought it was "warner" though it doesn't show up in the English dictionary and doesn't exactly sound right.
So I ask, what is the correct word if there even is one. If there isn't a correct word, what would be best to use as surely, "someone who warns" can't be?