Acute annoyance or disappointment (7)
I believe the answer is:
chagrin
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">acute annoyance</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(chagrin is annoyance or irritation)</span><br/ ><br/ >'<span class="explanation-format__original">disappointment</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for chagrin that I've seen before include "Shame at one's failure" , "Annoyance/shame at one's failure" , "Strong feeling of embarrassment" , "Frustration at having failed" , "Arching with annoyance and embarrassment" .)