Affair; collaboration (7)
I believe the answer is:
liaison
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">affair</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that affair can be written as liaison)</span><br/ ><br/ >'<span class="explanation-format__original">collaboration</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for liaison that I've seen before include "Sort of officer" , "Amour; communication" , "Mediator" , "Naughty affair?" , "A contact or affair" .)