overproof UK /(ˌ)əʊvəˈpɹuːf/US /ˌoʊvɚˈpɹuf/adjective 1noun 1verb 1forms 3 adjective1 •Possessing a higher proportion of alcohol than proof spirit.Leeward Island Rums are but seldom brought to this country at a higher rate of strength, than eight or ten per cent. overproof. — 1827 noun1 •A spirit possessing a higher proportion of alcohol than proof spirit.Bustle, Jack, bustle. Show us the best—the very best—the over-proof that you keep for your own drinking, Jack! — 1841 verb1 •To proof (allow dough containing yeast to rise) excessively.The product may have an open or irregular grain because of the following: a. Underproofing or Overproofing the Dough. b. Too Little Fermentation. c. Baking in an Oven That is Too Cool. — 1962 formsoverproofed · overproofing · overproofs