Requiring immediate attention (6)
I believe the answer is:
urgent
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">requiring immediate attention</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 urgent that I've seen before include "In need of immediate action" , "Demanding immediate attention" , "grave?" , "Pressing, imperative" , "Needing immediate attention, don't delay" .)