Almost never
I believe the answer is:
once
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">almost never</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for once that I've seen before include "Sometime" , "On a single (or past) occasion" , "In the old days" , "Cone (anag.)" , "In times past" .)