Imperative (5)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">imperative</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for essential that I've seen before include "something necessary" , "'Absolutely necessary, required (9)'" , "Type of oil" , "absolutely neccessary?" , "Vitally important" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">imperative</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 vital that I've seen before include "Most important, like certain body organs" , "Essential to life, indispensable" , "Imperative" , "Crucially important, essential" , "Urgently needed or absolutely necessary" .)