Invaluable (9)
I believe the answer is:
priceless
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">invaluable</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for priceless that I've seen before include "Wonderful" , "Hilarious -- extraordinarily precious" , "Of inestimable value" , "Very precious; absurd" , "of inestimable worth" .)