Adequate, acceptable (12)
I believe the answer is:
satisfactory
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">adequate</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">acceptable</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that acceptable can be written as satisfactory)</span><br/ ><br/ ></span>
(Other definitions for satisfactory that I've seen before include "Up to scratch" , "Fully acceptable" , "Fulfilling expectations" , "fine" , "unexceptional" .)