Hardly ever (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hardly ever</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for rarely that I've seen before include "Not done or occurring very often" , "Very occasionally" , "Not very often, seldom in fact" , "when hundred-to-one horse wins?" , "very well" .)
(Other definitions for seldom that I've seen before include "on rare occasions" , "Models (anag)" , "Not 21" , "Not very often, rarely" , "Alluvium" .)