Word of regret
I believe the answer is:
alas
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">word of regret</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for alas that I've seen before include "Expression of grief/pity" , "What a shame!" , "express regret thus" , "Regrettably, unfortunately" , "Too bad, so sad" .)