Relapse (7)
I believe the answer is:
setback
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">relapse</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for setback that I've seen before include "Problem" , "Hitch" , "Check" , "disappointment" , "Snag" .)