Very keen; enthusiastic (5)
I believe the answer is:
eager
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">very keen</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">enthusiastic</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for eager that I've seen before include "Keenly expectant" , "Swiss mountain" , "Keenly interested" , "Keen, avid" , "Earnest" .)