antimalarial drug an·ti·ma·larialdrug uncommon noun 1. a medicinal drug used to prevent or treat malaria Synonymsantimalarialantimalarial drug Related words Broader terms antiprotozoal Narrower terms chloroquinemefloquineprimaquinequinacrinequinine WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.