boil up verb 3noun 1forms 4 verb3 •To cook or prepare by boiling.Can you boil up the vegetables while I baste the meat? •(slang, old-fashioned) To boil clothes to clean or sanitize them. •To become more excited, intense or exciting. noun1 •(New-Zealand) A traditionally Māori soup/stew made with potatoes, pork and other ingredients. formsboiled up · boiling up · boils up · boil ups