Noah Webster's Dictionary 1. (n.) A green poisonous substance used as a pigment and drug, obtained by the action of acetic acid on copper, and consisting essentially of a complex mixture of several basic copper acetates. 2. (n.) The green rust formed on copper. 3. (v. t.) To cover, or coat, with verdigris. Int. Standard Bible Encyclopedia VERDIGRIS vur'-di-gres. See SCUM.