Was unwell
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">was unwell</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 ailed that I've seen before include "Troubled" , "Delia (anag.)" , "was giving trouble" , "Didn't feel well" , "Was unwell" .)