Determined effort (9)
I believe the answer is:
endeavour
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">determined effort</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 endeavour that I've seen before include "Strive - Inspector Morse's first name" , "The first handle inspector has" , "Aspire; attempt" , "Strive - over a nude (anag)" , "Try to achieve something" .)