Acquiescence (9)
I believe the answer is:
agreement
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">acquiescence</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for agreement that I've seen before include "Harmony, concurrence" , "Accord, contract" , "Correspondence" , "Pact" , "Harmony or treaty" .)