Almost certainly (8)
I believe the answer is:
probably
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">almost certainly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for probably that I've seen before include "Almost certainly" , "No doubt" , "In all likelihood" , "Most possibly" , "I expect so" .)