Isn't oneself (4)
(Other definitions for ails that I've seen before include "Is unwell - sail away" , "Is not well" , "languishes" , "Feels unwell" , "Troubles; afflicts" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">isn't oneself?</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 acts that I've seen before include "5th NT book" , "Biblical book" , "exerts influence" , "Dramatic parts" , "Cast in major divisions of plays, like Shakespeare's" .)