“+ transitive verb
Etymology: un- (II) + sell
1. : to dissuade from a belief in the truth, value, or desirability of something
has undertaken to unsell the American people on several debatable ideas … foisted on them — R.E.Lauterbach
others won't be able to unsell him on the things he's sold on — Time
2. : to dissuade one from a belief in the truth, value, or desirability of
comes to unsell the idea that his country wants war
rushed back before the press release to try to unsell the proposal