Disappointed, disillusioned (12)
I believe the answer is:
disenchanted
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">disappointed</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(disenchanting is a kind of disappointing)</span><br/ ><br/ >'<span class="explanation-format__original">disillusioned</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for disenchanted that I've seen before include "Saddened by frustrated expectations" , "Having lost one's fascination" , "Let down" .)