Be (5)
I believe the answer is:
exist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">be</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that be can be written as exist)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for exist that I've seen before include "Have being or continue living" , "Subsist" , "Survive" , "Scrape by" , "Get a life!" .)