Happy as a clam (6)
I believe the answer is:
elated
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">happy as a clam</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for elated that I've seen before include "Joyful, uplifted" , "Overjoyed, extremely pleased" , "Jubilant, very pleased" , "Full of high-spirited delight" , "Very pleased, quite high" .)