Entry 2 senses · 2 variants Webster, 1913 antitussive · IPA a. n. 01 a. having ability to to suppress or relieve coughing; -- of chemical substances. 1. having ability to to suppress or relieve coughing; -- of chemical substances. 02 n. a medicament used to suppress or relieve coughing; an antitussive substance. 1. a medicament used to suppress or relieve coughing; an antitussive substance.