Declare; maintain (6)
I believe the answer is:
assert
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">declare</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that assert is a type of declare)</span><br/ ><br/ >'<span class="explanation-format__original">maintain</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that maintain can be written as assert)</span><br/ ><br/ ></span>
(Other definitions for assert that I've seen before include "Swear" , "Maintain - allege" , "Declare, claim" , "State authoritatively" , "Aver, maintain" .)