Doubtless (6)
I believe the answer is:
surely
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">doubtless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for surely that I've seen before include "with firmness" , "Undoubtedly" , "Without doubt, certainly" , "With certainty" , "it would seem ironic?" .)