Active at night (9)
I believe the answer is:
nocturnal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">active at night</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 nocturnal that I've seen before include "Like owls and badgers" , "going abroad furtively?" , "Active at night" , "occurring at night" , "Relating to the night" .)