Definition of illegal. : not according to or authorized by law : unlawful, illicit; also : not sanctioned by official rules (as of a game)
antibiotic. n. 1. (Pharmacology) any of various chemical substances, such as penicillin, streptomycin, chloramphenicol, and tetracycline, produced by various microorganisms, esp fungi, or made synthetically and capable of destroying or inhibiting the growth of microorganisms, esp bacteria. adj.
Difference Between Antibiotic and Antimicrobial. Antimicrobials are agents that act across a wide range of organisms including bacteria, viruses, fungal, protozoa, and helminthes. Antibiotics belong to a sub category of that large group and include substances that have the ability to kill and stop the growth of bacteria.