antifouling adjective 1noun 1forms 1 adjective1 •That prevents or counteracts the buildup of barnacles and other deposits on undersea surfaces such as those of boats. noun1 •Any substance that prevents or counteracts the buildup of barnacles and other deposits on undersea surfaces such as those of boats.These antifoulings release the biocides by a hydrolysis or ion exchange reaction of an acrylic polymer with seawater. — 2002 formsantifoulings