Spot on (5)
I believe the answer is:
exact
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">spot on</span>' is the definition.<br/ ><span class="explanation-format__explanation">(spot on means exactly right)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for exact that I've seen before include "totally accurate" , "Specific" , "Demand and obtain" , "far from improvised?" , "without rounding" .)