overcoat UK /ˈəʊvəkəʊt/US /ˈoʊvɚkoʊt/noun 2verb 1forms 3 noun2 •A heavy garment worn over other clothes, for protection from cold or weather.Men that I knew around Wapatomac didn't wear high, shiny plug hats, nor yeller spring overcoats, nor carry canes with ivory heads as big as a catboat's anchor, as you might say. — 1913 •An outer coat, an outer coating (of paint, etc).Wait 24 hours before applying an overcoat. verb1 •To apply an exterior coating to.Wait 24 hours before overcoating with either this product or a clearcoat. formsovercoated · overcoating · overcoats