Sadly (5,2,3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sadly</span>' is the definition.<br/ ><span class="explanation-format__explanation">('alas' is used to express regret)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for alas that I've seen before include "Sad to say!" , "Cry of woe" , "Proper, respectable" , "Archaic exclamation of sorrow or regret" , "Regretfully!" .)