undercoat Syllabification: (un·der·coat)Pronunciation: /ˈəndərˌkōt/Translate undercoat | into French | into German | into Italian | into Spanish Definition of undercoat noun 1a layer of paint applied after the primer and before the topcoat. 2an animal’s underfur or down. verb [with object] apply a coat of undercoat to (something). undercoat in other Oxford dictionaries Definition of undercoat in the British & World English dictionary