Unostentatious (6)
I believe the answer is:
modest
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unostentatious</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for modest that I've seen before include "'Unassuming, diffident (6)'" , "Demure" , "Not boastful" , "Lacking vanity" , "Not conceited, unassuming" .)