Self-evident (9)
I believe the answer is:
axiomatic
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">self-evident</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for axiomatic that I've seen before include "Self-evidently true" , "Taken for granted" , "Accepted" , "Given" , "Pertaining to self-evident truths" .)