antibiotic
antibiotic , noun
1.
A chemical substance derived from a mold or bacterium that kills microorganisms and cures infections.
2.
any chemical substance having therapeutically useful antibacterial or antifungal activity; -- used commonly but loosely for synthetic as well as natural antimicrobial agents.
antibiotic , adjective
1.
of or pertaining to an antibiotic.
2.
having antimicrobial activity; capable of killing microbes.