Weirdly (6)
I believe the answer is:
eerily
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">weirdly</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 eerily that I've seen before include "in a disturbing way" , "In a strange and frightening way" , "In a strange and frightening manner" , "alarmingly" , "In strange or unearthly way" .)