You should be so hyped up about how dumb it is to use “adversive” that you’d spot it immediately on a written quiz and get full credit for correcting it. And, of course your sly but caring instructor might occasionally slip an “adversive” into her or his lecture, just to give you an opportunity to correct it. When that happens, feel free to blurt out, “I heard the really dumb thing you said!” She will probably be so impressed she’ll offer you a full-ride assistantship on the spot.