unsell

un- +‎ sell

unsell (third-person singular simple present unsells, present participle unselling, simple past and past participle unsold)

1. (transitive) To cause to appear less attractive to consumers or adherents.
   • 1983, Thomas C. Kinnear, Kenneth L. Bernhardt, Dynamics of marketing principles: a reader

     At the same time, every effort to unsell something may also be viewed as an effort to sell something else. Those who attempt to unsell cigarette smoking are attempting to sell health...

   • 2007 December 9, Robert A. Lopes; As Told To Amy Zipkin, “A Sporting Chance”, in New York Times‎:

     After the meeting Bob grabbed me by the ear and told me, "Once you make the sale, shut up and don't unsell it."

• sullen