Antibiotic drug (10)
I believe the answer is:
penicillin
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">antibiotic drug</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that penicillin is a type of antibiotic drug)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for penicillin that I've seen before include "17" , "Common antibiotic" .)