A synthetic substance is a material created by humans through chemical processes. The two crossword solutions for this term are RESIN and PLASTIC. RESIN is a solid or semi-solid material made from a variety of organic compounds, typically used in adhesives, coatings, and plastics. PLASTIC is a synthetic material made from a wide range of organic polymers, such as polyethylene, nylon, and polypropylene, that can be molded into solid objects.