alkaloid

al·ka·loid

noun \ˈal-kə-ˌlȯid\

Definition of ALKALOID

: any of numerous usually colorless, complex, and bitter organic bases (as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active

—al·ka·loi·dal \ˌal-kə-ˈlȯid-^əl\ adjective