a. 1. having ability to to suppress or relieve coughing; -- of chemical substances. [ WordNet 1.5 +PJC ]
n. 1. a medicament used to suppress or relieve coughing; an antitussive substance. Codeine is one such commonly used antitussive. [ WordNet 1.5 +PJC ]
a. (Med.) Pertaining to a cough; caused by coughing. [ Webster 1913 Suppl. ]