Reveal unintentionally (6)
I believe the answer is:
betray
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">reveal unintentionally</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for betray that I've seen before include "Be disloyal to like Judas" , "Expose" , "Deliver to an enemy by treachery" , "Act treacherously towards (someone)" , "shop" .)