Tranquillises (7)
I believe the answer is:
sedates
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tranquillises</span>' is the definition.<br/ ><span class="explanation-format__explanation">('sedate' can be a synonym of 'tranquillize')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sedates that I've seen before include "Treats with soothing or sleeping drugs" , "keeps quiet" , "Anaesthetises" , "Calms" .)