Being of the same opinion (8)
I believe the answer is:
agreeing
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">being of the same opinion</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for agreeing that I've seen before include "OK" , "In concurrence" , "Concurring" , "Correspondent" , "Consenting" .)