Insanity (7)
I believe the answer is:
madness
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">insanity</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that insanity can be written as madness)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for madness that I've seen before include "great anger" , "Irrationality" , "Lunacy - ska/pop band" , "Group" , "Folly" .)