Polite, courteous (5)
I believe the answer is:
civil
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">polite</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">courteous</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for civil that I've seen before include "Urbane" , "Not rude" , "Relating to citizens" , "Courteous, polite" , "Courteously polite" .)